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su without password via /proc/pid/mem write #2

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andrew-aladev opened this Issue Jan 23, 2012 · 1 comment

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@andrew-aladev

andrew-aladev commented Jan 23, 2012

http://blog.zx2c4.com/749
your fs/proc/base.c is vulnerable too

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

usb/isp1760: Simpler queue head list code.
Small code refactoring to ease the real fix in patch #2.

Signed-off-by: Arvid Brodin <arvid.brodin@enea.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

Sarang Radke James Bottomley
[SCSI] qla4xxx: fix call trace on rmmod with ql4xdontresethba=1
abort all active commands from eh_host_reset in-case
of ql4xdontresethba=1

Fix following call trace:-
Nov 21 14:50:47 172.17.140.111 qla4xxx 0000:13:00.4: qla4_8xxx_disable_msix: qla4xxx (rsp_q)
Nov 21 14:50:47 172.17.140.111 qla4xxx 0000:13:00.4: PCI INT A disabled
Nov 21 14:50:47 172.17.140.111 slab error in kmem_cache_destroy(): cache `qla4xxx_srbs': Can't free all objects
Nov 21 14:50:47 172.17.140.111 Pid: 9154, comm: rmmod Tainted: G           O 3.2.0-rc2+ #2
Nov 21 14:50:47 172.17.140.111 Call Trace:
Nov 21 14:50:47 172.17.140.111  [<c051231a>] ? kmem_cache_destroy+0x9a/0xb0
Nov 21 14:50:47 172.17.140.111  [<c0489c4a>] ? sys_delete_module+0x14a/0x210
Nov 21 14:50:47 172.17.140.111  [<c04fd552>] ? do_munmap+0x202/0x280
Nov 21 14:50:47 172.17.140.111  [<c04a6d4e>] ? audit_syscall_entry+0x1ae/0x1d0
Nov 21 14:50:47 172.17.140.111  [<c083019f>] ? sysenter_do_call+0x12/0x28
Nov 21 14:51:50 172.17.140.111 SLAB: cache with size 64 has lost its name
Nov 21 14:51:50 172.17.140.111 iscsi: registered transport (qla4xxx)
Nov 21 14:51:50 172.17.140.111 qla4xxx 0000:13:00.4: PCI INT A -> GSI 28 (level, low) -> IRQ 28

Signed-off-by: Sarang Radke <sarang.radke@qlogic.com>
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

[S390] kvm: fix sleeping function ... at mm/page_alloc.c:2260
commit cc77245
    [S390] fix list corruption in gmap reverse mapping

added a potential dead lock:

BUG: sleeping function called from invalid context at mm/page_alloc.c:2260
in_atomic(): 1, irqs_disabled(): 0, pid: 1108, name: qemu-system-s39
3 locks held by qemu-system-s39/1108:
 #0:  (&kvm->slots_lock){+.+.+.}, at: [<000003e004866542>] kvm_set_memory_region+0x3a/0x6c [kvm]
 #1:  (&mm->mmap_sem){++++++}, at: [<0000000000123790>] gmap_map_segment+0x9c/0x298
 #2:  (&(&mm->page_table_lock)->rlock){+.+.+.}, at: [<00000000001237a8>] gmap_map_segment+0xb4/0x298
CPU: 0 Not tainted 3.1.3 #45
Process qemu-system-s39 (pid: 1108, task: 00000004f8b3cb30, ksp: 00000004fd5978d0)
00000004fd5979a0 00000004fd597920 0000000000000002 0000000000000000
       00000004fd5979c0 00000004fd597938 00000004fd597938 0000000000617e96
       0000000000000000 00000004f8b3cf58 0000000000000000 0000000000000000
       000000000000000d 000000000000000c 00000004fd597988 0000000000000000
       0000000000000000 0000000000100a18 00000004fd597920 00000004fd597960
Call Trace:
([<0000000000100926>] show_trace+0xee/0x144)
 [<0000000000131f3a>] __might_sleep+0x12a/0x158
 [<0000000000217fb4>] __alloc_pages_nodemask+0x224/0xadc
 [<0000000000123086>] gmap_alloc_table+0x46/0x114
 [<000000000012395c>] gmap_map_segment+0x268/0x298
 [<000003e00486b014>] kvm_arch_commit_memory_region+0x44/0x6c [kvm]
 [<000003e004866414>] __kvm_set_memory_region+0x3b0/0x4a4 [kvm]
 [<000003e004866554>] kvm_set_memory_region+0x4c/0x6c [kvm]
 [<000003e004867c7a>] kvm_vm_ioctl+0x14a/0x314 [kvm]
 [<0000000000292100>] do_vfs_ioctl+0x94/0x588
 [<0000000000292688>] SyS_ioctl+0x94/0xac
 [<000000000061e124>] sysc_noemu+0x22/0x28
 [<000003fffcd5e7ca>] 0x3fffcd5e7ca
3 locks held by qemu-system-s39/1108:
 #0:  (&kvm->slots_lock){+.+.+.}, at: [<000003e004866542>] kvm_set_memory_region+0x3a/0x6c [kvm]
 #1:  (&mm->mmap_sem){++++++}, at: [<0000000000123790>] gmap_map_segment+0x9c/0x298
 #2:  (&(&mm->page_table_lock)->rlock){+.+.+.}, at: [<00000000001237a8>] gmap_map_segment+0xb4/0x298

Fix this by freeing the lock on the alloc path. This is ok, since the
gmap table is never freed until we call gmap_free, so the table we are
walking cannot go.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s.  The code is slightly
broken and misleading.

The lockless part is in mempool_free().  It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock.  Two things need to be guaranteed for correct
operation.

1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.

For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment).  For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers.  To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr.  IOW,

	ALLOCATING TASK			FREEING TASK

	update pool state after alloc;
	wmb();
	pass pointer to freeing task;
					read pointer;
					rmb();
					read pool state to free;

The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock.  smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().

For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up.  Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.

Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait.  There is no reason to do unlock - add waitqueue -
test condition again.  It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.

This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition.  More importantly, it explains what memory
barriers do and how the lockless testing is correct.

-v2: Oleg pointed out that unlock doesn't imply wmb.  Added explicit
     smp_wmb() after successful allocation from reserved pool and
     updated comments accordingly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

net: introduce res_counter_charge_nofail() for socket allocations
There is a case in __sk_mem_schedule(), where an allocation
is beyond the maximum, but yet we are allowed to proceed.
It happens under the following condition:

	sk->sk_wmem_queued + size >= sk->sk_sndbuf

The network code won't revert the allocation in this case,
meaning that at some point later it'll try to do it. Since
this is never communicated to the underlying res_counter
code, there is an inbalance in res_counter uncharge operation.

I see two ways of fixing this:

1) storing the information about those allocations somewhere
   in memcg, and then deducting from that first, before
   we start draining the res_counter,
2) providing a slightly different allocation function for
   the res_counter, that matches the original behavior of
   the network code more closely.

I decided to go for #2 here, believing it to be more elegant,
since #1 would require us to do basically that, but in a more
obscure way.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
CC: Tejun Heo <tj@kernel.org>
CC: Li Zefan <lizf@cn.fujitsu.com>
CC: Laurent Chavey <chavey@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

HID: usbhid: fix dead lock between open and disconect
There is no reason to hold hiddev->existancelock before
calling usb_deregister_dev, so move it out of the lock.

The patch fixes the lockdep warning below.

[ 5733.386271] ======================================================
[ 5733.386274] [ INFO: possible circular locking dependency detected ]
[ 5733.386278] 3.2.0-custom-next-20120111+ #1 Not tainted
[ 5733.386281] -------------------------------------------------------
[ 5733.386284] khubd/186 is trying to acquire lock:
[ 5733.386288]  (minor_rwsem){++++.+}, at: [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386311]
[ 5733.386312] but task is already holding lock:
[ 5733.386315]  (&hiddev->existancelock){+.+...}, at: [<ffffffffa0094d17>] hiddev_disconnect+0x26/0x87 [usbhid]
[ 5733.386328]
[ 5733.386329] which lock already depends on the new lock.
[ 5733.386330]
[ 5733.386333]
[ 5733.386334] the existing dependency chain (in reverse order) is:
[ 5733.386336]
[ 5733.386337] -> #1 (&hiddev->existancelock){+.+...}:
[ 5733.386346]        [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386357]        [<ffffffff813df961>] __mutex_lock_common+0x60/0x465
[ 5733.386366]        [<ffffffff813dfe4d>] mutex_lock_nested+0x36/0x3b
[ 5733.386371]        [<ffffffffa0094ad6>] hiddev_open+0x113/0x193 [usbhid]
[ 5733.386378]        [<ffffffffa0011971>] usb_open+0x66/0xc2 [usbcore]
[ 5733.386390]        [<ffffffff8111a8b5>] chrdev_open+0x12b/0x154
[ 5733.386402]        [<ffffffff811159a8>] __dentry_open.isra.16+0x20b/0x355
[ 5733.386408]        [<ffffffff811165dc>] nameidata_to_filp+0x43/0x4a
[ 5733.386413]        [<ffffffff81122ed5>] do_last+0x536/0x570
[ 5733.386419]        [<ffffffff8112300b>] path_openat+0xce/0x301
[ 5733.386423]        [<ffffffff81123327>] do_filp_open+0x33/0x81
[ 5733.386427]        [<ffffffff8111664d>] do_sys_open+0x6a/0xfc
[ 5733.386431]        [<ffffffff811166fb>] sys_open+0x1c/0x1e
[ 5733.386434]        [<ffffffff813e7c79>] system_call_fastpath+0x16/0x1b
[ 5733.386441]
[ 5733.386441] -> #0 (minor_rwsem){++++.+}:
[ 5733.386448]        [<ffffffff8108255d>] __lock_acquire+0xa80/0xd74
[ 5733.386454]        [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386458]        [<ffffffff813e01f5>] down_write+0x44/0x77
[ 5733.386464]        [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386475]        [<ffffffffa0094d2d>] hiddev_disconnect+0x3c/0x87 [usbhid]
[ 5733.386483]        [<ffffffff8132df51>] hid_disconnect+0x3f/0x54
[ 5733.386491]        [<ffffffff8132dfb4>] hid_device_remove+0x4e/0x7a
[ 5733.386496]        [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386502]        [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386507]        [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386512]        [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386519]        [<ffffffff8132def3>] hid_destroy_device+0x1e/0x3d
[ 5733.386525]        [<ffffffffa00916b0>] usbhid_disconnect+0x36/0x42 [usbhid]
[ 5733.386530]        [<ffffffffa000fb60>] usb_unbind_interface+0x57/0x11f [usbcore]
[ 5733.386542]        [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386547]        [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386552]        [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386557]        [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386562]        [<ffffffffa000de61>] usb_disable_device+0xa8/0x1d8 [usbcore]
[ 5733.386573]        [<ffffffffa0006bd2>] usb_disconnect+0xab/0x11f [usbcore]
[ 5733.386583]        [<ffffffffa0008aa0>] hub_thread+0x73b/0x1157 [usbcore]
[ 5733.386593]        [<ffffffff8105dc0f>] kthread+0x95/0x9d
[ 5733.386601]        [<ffffffff813e90b4>] kernel_thread_helper+0x4/0x10
[ 5733.386607]
[ 5733.386608] other info that might help us debug this:
[ 5733.386609]
[ 5733.386612]  Possible unsafe locking scenario:
[ 5733.386613]
[ 5733.386615]        CPU0                    CPU1
[ 5733.386618]        ----                    ----
[ 5733.386620]   lock(&hiddev->existancelock);
[ 5733.386625]                                lock(minor_rwsem);
[ 5733.386630]                                lock(&hiddev->existancelock);
[ 5733.386635]   lock(minor_rwsem);
[ 5733.386639]
[ 5733.386640]  *** DEADLOCK ***
[ 5733.386641]
[ 5733.386644] 6 locks held by khubd/186:
[ 5733.386646]  #0:  (&__lockdep_no_validate__){......}, at: [<ffffffffa00084af>] hub_thread+0x14a/0x1157 [usbcore]
[ 5733.386661]  #1:  (&__lockdep_no_validate__){......}, at: [<ffffffffa0006b77>] usb_disconnect+0x50/0x11f [usbcore]
[ 5733.386677]  #2:  (hcd->bandwidth_mutex){+.+.+.}, at: [<ffffffffa0006bc8>] usb_disconnect+0xa1/0x11f [usbcore]
[ 5733.386693]  #3:  (&__lockdep_no_validate__){......}, at: [<ffffffff812c09bb>] device_release_driver+0x18/0x2d
[ 5733.386704]  #4:  (&__lockdep_no_validate__){......}, at: [<ffffffff812c09bb>] device_release_driver+0x18/0x2d
[ 5733.386714]  #5:  (&hiddev->existancelock){+.+...}, at: [<ffffffffa0094d17>] hiddev_disconnect+0x26/0x87 [usbhid]
[ 5733.386727]
[ 5733.386727] stack backtrace:
[ 5733.386731] Pid: 186, comm: khubd Not tainted 3.2.0-custom-next-20120111+ #1
[ 5733.386734] Call Trace:
[ 5733.386741]  [<ffffffff81062881>] ? up+0x34/0x3b
[ 5733.386747]  [<ffffffff813d9ef3>] print_circular_bug+0x1f8/0x209
[ 5733.386752]  [<ffffffff8108255d>] __lock_acquire+0xa80/0xd74
[ 5733.386756]  [<ffffffff810808b4>] ? trace_hardirqs_on_caller+0x15d/0x1a3
[ 5733.386763]  [<ffffffff81043a3f>] ? vprintk+0x3f4/0x419
[ 5733.386774]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386779]  [<ffffffff81082d26>] lock_acquire+0xcb/0x10e
[ 5733.386789]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386797]  [<ffffffff813e01f5>] down_write+0x44/0x77
[ 5733.386807]  [<ffffffffa0011a04>] ? usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386818]  [<ffffffffa0011a04>] usb_deregister_dev+0x37/0x9e [usbcore]
[ 5733.386825]  [<ffffffffa0094d2d>] hiddev_disconnect+0x3c/0x87 [usbhid]
[ 5733.386830]  [<ffffffff8132df51>] hid_disconnect+0x3f/0x54
[ 5733.386834]  [<ffffffff8132dfb4>] hid_device_remove+0x4e/0x7a
[ 5733.386839]  [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386844]  [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386848]  [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386854]  [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386859]  [<ffffffff8132def3>] hid_destroy_device+0x1e/0x3d
[ 5733.386865]  [<ffffffffa00916b0>] usbhid_disconnect+0x36/0x42 [usbhid]
[ 5733.386876]  [<ffffffffa000fb60>] usb_unbind_interface+0x57/0x11f [usbcore]
[ 5733.386882]  [<ffffffff812c0957>] __device_release_driver+0x81/0xcd
[ 5733.386886]  [<ffffffff812c09c3>] device_release_driver+0x20/0x2d
[ 5733.386890]  [<ffffffff812c0564>] bus_remove_device+0x114/0x128
[ 5733.386895]  [<ffffffff812bdd6f>] device_del+0x131/0x183
[ 5733.386905]  [<ffffffffa000de61>] usb_disable_device+0xa8/0x1d8 [usbcore]
[ 5733.386916]  [<ffffffffa0006bd2>] usb_disconnect+0xab/0x11f [usbcore]
[ 5733.386921]  [<ffffffff813dff82>] ? __mutex_unlock_slowpath+0x130/0x141
[ 5733.386929]  [<ffffffffa0008aa0>] hub_thread+0x73b/0x1157 [usbcore]
[ 5733.386935]  [<ffffffff8106a51d>] ? finish_task_switch+0x78/0x150
[ 5733.386941]  [<ffffffff8105e396>] ? __init_waitqueue_head+0x4c/0x4c
[ 5733.386950]  [<ffffffffa0008365>] ? usb_remote_wakeup+0x56/0x56 [usbcore]
[ 5733.386955]  [<ffffffff8105dc0f>] kthread+0x95/0x9d
[ 5733.386961]  [<ffffffff813e90b4>] kernel_thread_helper+0x4/0x10
[ 5733.386966]  [<ffffffff813e24b8>] ? retint_restore_args+0x13/0x13
[ 5733.386970]  [<ffffffff8105db7a>] ? __init_kthread_worker+0x55/0x55
[ 5733.386974]  [<ffffffff813e90b0>] ? gs_change+0x13/0x13

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

Stefano Stabellini Konrad Rzeszutek Wilk
xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback
CC: stable@kernel.org #2.6.37 and onwards
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGE…
…S block during isolation for migration

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 #1 [d72d3b24] oops_end at c05c5322
 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 #3 [d72d3bec] bad_area at c0227fb6
 #4 [d72d3c00] do_page_fault at c05c72ec
 #5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 #6 [d72d3cb4] isolate_migratepages at c030b15a
 #7 [d72d3d14] zone_watermark_ok at c02d26cb
 #8 [d72d3d2c] compact_zone at c030b8de
 #9 [d72d3d68] compact_zone_order at c030bba1
#10 [d72d3db4] try_to_compact_pages at c030bc84
#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
#14 [d72d3eb8] alloc_pages_vma at c030a845
#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
#16 [d72d3f00] handle_mm_fault at c02f36c6
#17 [d72d3f30] do_page_fault at c05c70ed
#18 [d72d3fb0] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 00000431
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

Merge tag 'sound-fixes' of git://git.kernel.org/pub/scm/linux/kernel/…
…git/tiwai/sound

sound fixes #2 for 3.3-rc3

A collection of small fixes, mostly for regressions.
In addition, a few ASoC wm8994 updates are included, too.

* tag 'sound-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ASoC: wm8994: Disable line output discharge prior to ramping VMID
  ASoC: wm8994: Fix typo in VMID ramp setting
  ALSA: oxygen, virtuoso: fix exchanged L/R volumes of aux and CD inputs
  ALSA: usb-audio: add Edirol UM-3G support
  ALSA: hda - add support for Uniwill ECS M31EI notebook
  ALSA: hda - Fix error handling in patch_ca0132.c
  ASoC: wm8994: Enabling VMID should take a runtime PM reference
  ALSA: hda/realtek - Fix a wrong condition
  ALSA: emu8000: Remove duplicate linux/moduleparam.h include from emu8000_patch.c
  ALSA: hda/realtek - Add missing Bass and CLFE as vmaster slaves
  ASoC: wm_hubs: Correct line input to line output 2 paths
  ASoC: cs42l73: Fix Output [X|A|V]SP_SCLK Sourcing Mode setting for master mode
  ASoC: wm8962: Fix word length configuration
  ASoC: core: Better support for idle_bias_off suspend ignores
  ASoC: wm8994: Remove ASoC level register cache sync
  ASoC: wm_hubs: Fix routing of input PGAs to line output mixer

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

ixgbe: do not update real num queues when netdev is going away
If the netdev is already in NETREG_UNREGISTERING/_UNREGISTERED state, do not
update the real num tx queues. netdev_queue_update_kobjects() is already
called via remove_queue_kobjects() at NETREG_UNREGISTERING time. So, when
upper layer driver, e.g., FCoE protocol stack is monitoring the netdev
event of NETDEV_UNREGISTER and calls back to LLD ndo_fcoe_disable() to remove
extra queues allocated for FCoE, the associated txq sysfs kobjects are already
removed, and trying to update the real num queues would cause something like
below:

...
PID: 25138  TASK: ffff88021e64c440  CPU: 3   COMMAND: "kworker/3:3"
 #0 [ffff88021f007760] machine_kexec at ffffffff810226d9
 #1 [ffff88021f0077d0] crash_kexec at ffffffff81089d2d
 #2 [ffff88021f0078a0] oops_end at ffffffff813bca78
 #3 [ffff88021f0078d0] no_context at ffffffff81029e72
 #4 [ffff88021f007920] __bad_area_nosemaphore at ffffffff8102a155
 #5 [ffff88021f0079f0] bad_area_nosemaphore at ffffffff8102a23e
 #6 [ffff88021f007a00] do_page_fault at ffffffff813bf32e
 #7 [ffff88021f007b10] page_fault at ffffffff813bc045
    [exception RIP: sysfs_find_dirent+17]
    RIP: ffffffff81178611  RSP: ffff88021f007bc0  RFLAGS: 00010246
    RAX: ffff88021e64c440  RBX: ffffffff8156cc63  RCX: 0000000000000004
    RDX: ffffffff8156cc63  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88021f007be0   R8: 0000000000000004   R9: 0000000000000008
    R10: ffffffff816fed00  R11: 0000000000000004  R12: 0000000000000000
    R13: ffffffff8156cc63  R14: 0000000000000000  R15: ffff8802222a0000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffff88021f007be8] sysfs_get_dirent at ffffffff81178c07
 #9 [ffff88021f007c18] sysfs_remove_group at ffffffff8117ac27
#10 [ffff88021f007c48] netdev_queue_update_kobjects at ffffffff813178f9
#11 [ffff88021f007c88] netif_set_real_num_tx_queues at ffffffff81303e38
#12 [ffff88021f007cc8] ixgbe_set_num_queues at ffffffffa0249763 [ixgbe]
#13 [ffff88021f007cf8] ixgbe_init_interrupt_scheme at ffffffffa024ea89 [ixgbe]
#14 [ffff88021f007d48] ixgbe_fcoe_disable at ffffffffa0267113 [ixgbe]
#15 [ffff88021f007d68] vlan_dev_fcoe_disable at ffffffffa014fef5 [8021q]
#16 [ffff88021f007d78] fcoe_interface_cleanup at ffffffffa02b7dfd [fcoe]
#17 [ffff88021f007df8] fcoe_destroy_work at ffffffffa02b7f08 [fcoe]
#18 [ffff88021f007e18] process_one_work at ffffffff8105d7ca
#19 [ffff88021f007e68] worker_thread at ffffffff81060513
#20 [ffff88021f007ee8] kthread at ffffffff810648b6
#21 [ffff88021f007f48] kernel_thread_helper at ffffffff813c40f4

Signed-off-by: Yi Zou <yi.zou@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

Bluetooth: Fix potential deadlock
We don't need to use the _sync variant in hci_conn_hold and
hci_conn_put to cancel conn->disc_work delayed work. This way
we avoid potential deadlocks like this one reported by lockdep.

======================================================
[ INFO: possible circular locking dependency detected ]
3.2.0+ #1 Not tainted
-------------------------------------------------------
kworker/u:1/17 is trying to acquire lock:
 (&hdev->lock){+.+.+.}, at: [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]

but task is already holding lock:
 ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 ((&(&conn->disc_work)->work)){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff81034ed1>] wait_on_work+0x3d/0xaa
       [<ffffffff81035b54>] __cancel_work_timer+0xac/0xef
       [<ffffffff81035ba4>] cancel_delayed_work_sync+0xd/0xf
       [<ffffffffa00554b0>] smp_chan_create+0xde/0xe6 [bluetooth]
       [<ffffffffa0056160>] smp_conn_security+0xa3/0x12d [bluetooth]
       [<ffffffffa0053640>] l2cap_connect_cfm+0x237/0x2e8 [bluetooth]
       [<ffffffffa004239c>] hci_proto_connect_cfm+0x2d/0x6f [bluetooth]
       [<ffffffffa0046ea5>] hci_event_packet+0x29d1/0x2d60 [bluetooth]
       [<ffffffffa003dde3>] hci_rx_work+0xd0/0x2e1 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

-> #1 (slock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e553a>] _raw_spin_lock_bh+0x36/0x6a
       [<ffffffff81244d56>] lock_sock_nested+0x24/0x7f
       [<ffffffffa004d96f>] lock_sock+0xb/0xd [bluetooth]
       [<ffffffffa0052906>] l2cap_chan_connect+0xa9/0x26f [bluetooth]
       [<ffffffffa00545f8>] l2cap_sock_connect+0xb3/0xff [bluetooth]
       [<ffffffff81243b48>] sys_connect+0x69/0x8a
       [<ffffffff812e6579>] system_call_fastpath+0x16/0x1b

-> #0 (&hdev->lock){+.+.+.}:
       [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
       [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
       [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

other info that might help us debug this:

Chain exists of:
  &hdev->lock --> slock-AF_BLUETOOTH-BTPROTO_L2CAP --> (&(&conn->disc_work)->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((&(&conn->disc_work)->work));
                               lock(slock-AF_BLUETOOTH-BTPROTO_L2CAP);
                               lock((&(&conn->disc_work)->work));
  lock(&hdev->lock);

 *** DEADLOCK ***

2 locks held by kworker/u:1/17:
 #0:  (hdev->name){.+.+.+}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf
 #1:  ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

stack backtrace:
Pid: 17, comm: kworker/u:1 Not tainted 3.2.0+ #1
Call Trace:
 [<ffffffff812e06c6>] print_circular_bug+0x1f8/0x209
 [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
 [<ffffffff81021ef2>] ? arch_local_irq_restore+0x6/0xd
 [<ffffffff81022bc7>] ? vprintk+0x3f9/0x41e
 [<ffffffff81057444>] lock_acquire+0x8a/0xa7
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff81190fd6>] ? __dynamic_pr_debug+0x6d/0x6f
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff8105320f>] ? trace_hardirqs_off+0xd/0xf
 [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
 [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff810357af>] process_one_work+0x178/0x2bf
 [<ffffffff81035751>] ? process_one_work+0x11a/0x2bf
 [<ffffffff81055af3>] ? lock_acquired+0x1d0/0x1df
 [<ffffffffa00410f3>] ? hci_acl_disconn+0x65/0x65 [bluetooth]
 [<ffffffff81036178>] worker_thread+0xce/0x152
 [<ffffffff810407ed>] ? finish_task_switch+0x45/0xc5
 [<ffffffff810360aa>] ? manage_workers.isra.25+0x16a/0x16a
 [<ffffffff81039a03>] kthread+0x95/0x9d
 [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10
 [<ffffffff812e5db4>] ? retint_restore_args+0x13/0x13
 [<ffffffff8103996e>] ? __init_kthread_worker+0x55/0x55
 [<ffffffff812e7750>] ? gs_change+0x13/0x13

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Reviewed-by: Ulisses Furquim <ulisses@profusion.mobi>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

richo pushed a commit to richo/linux that referenced this issue Mar 6, 2012

mlx4: Replacing pool_lock with mutex
Under the spinlock we call request_irq(), which allocates memory with GFP_KERNEL,
This causes the following trace when DEBUG_SPINLOCK is enabled, it can cause
the following trace:

 BUG: spinlock wrong CPU on CPU#2, ethtool/2595
 lock: ffff8801f9cbc2b0, .magic: dead4ead, .owner: ethtool/2595, .owner_cpu: 0
 Pid: 2595, comm: ethtool Not tainted 3.0.18 #2
 Call Trace:
 spin_bug+0xa2/0xf0
 do_raw_spin_unlock+0x71/0xa0
 _raw_spin_unlock+0xe/0x10
 mlx4_assign_eq+0x12b/0x190 [mlx4_core]
 mlx4_en_activate_cq+0x252/0x2d0 [mlx4_en]
 ? mlx4_en_activate_rx_rings+0x227/0x370 [mlx4_en]
 mlx4_en_start_port+0x189/0xb90 [mlx4_en]
 mlx4_en_set_ringparam+0x29a/0x340 [mlx4_en]
 dev_ethtool+0x816/0xb10
 ? dev_get_by_name_rcu+0xa4/0xe0
 dev_ioctl+0x2b5/0x470
 handle_mm_fault+0x1cd/0x2d0
 sock_do_ioctl+0x5d/0x70
 sock_ioctl+0x79/0x2f0
 do_vfs_ioctl+0x8c/0x340
 sys_ioctl+0xa1/0xb0
 system_call_fastpath+0x16/0x1b

Replacing with mutex, which is enough in this case.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

bootc pushed a commit to bootc/linux-rpi-orig that referenced this issue May 8, 2012

mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGE…
…S block during isolation for migration

commit 0bf380b upstream.

When isolating for migration, migration starts at the start of a zone
which is not necessarily pageblock aligned.  Further, it stops isolating
when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally
not aligned.  This allows isolate_migratepages() to call pfn_to_page() on
an invalid PFN which can result in a crash.  This was originally reported
against a 3.0-based kernel with the following trace in a crash dump.

PID: 9902   TASK: d47aecd0  CPU: 0   COMMAND: "memcg_process_s"
 #0 [d72d3ad0] crash_kexec at c028cfdb
 #1 [d72d3b24] oops_end at c05c5322
 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60
 #3 [d72d3bec] bad_area at c0227fb6
 #4 [d72d3c00] do_page_fault at c05c72ec
 #5 [d72d3c80] error_code (via page_fault) at c05c47a4
    EAX: 00000000  EBX: 000c0000  ECX: 00000001  EDX: 00000807  EBP: 000c0000
    DS:  007b      ESI: 00000001  ES:  007b      EDI: f3000a80  GS:  6f50
    CS:  0060      EIP: c030b15a  ERR: ffffffff  EFLAGS: 00010002
 #6 [d72d3cb4] isolate_migratepages at c030b15a
 #7 [d72d3d14] zone_watermark_ok at c02d26cb
 #8 [d72d3d2c] compact_zone at c030b8de
 #9 [d72d3d68] compact_zone_order at c030bba1
#10 [d72d3db4] try_to_compact_pages at c030bc84
#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7
#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7
#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97
#14 [d72d3eb8] alloc_pages_vma at c030a845
#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb
#16 [d72d3f00] handle_mm_fault at c02f36c6
#17 [d72d3f30] do_page_fault at c05c70ed
#18 [d72d3fb0] error_code (via page_fault) at c05c47a4
    EAX: b71ff00  EBX: 00000001  ECX: 00001600  EDX: 00000431
    DS:  007b      ESI: 08048950  ES:  007b      EDI: bfaa3788
    SS:  007b      ESP: bfaa36e0  EBP: bfaa3828  GS:  6f50
    CS:  0073      EIP: 080487c8  ERR: ffffffff  EFLAGS: 00010202

It was also reported by Herbert van den Bergh against 3.1-based kernel
with the following snippet from the console log.

BUG: unable to handle kernel paging request at 01c00008
IP: [<c0522399>] isolate_migratepages+0x119/0x390
*pdpt = 000000002f7ce001 *pde = 0000000000000000

It is expected that it also affects 3.2.x and current mainline.

The problem is that pfn_valid is only called on the first PFN being
checked and that PFN is not necessarily aligned.  Lets say we have a case
like this

H = MAX_ORDER_NR_PAGES boundary
| = pageblock boundary
m = cc->migrate_pfn
f = cc->free_pfn
o = memory hole

H------|------H------|----m-Hoooooo|ooooooH-f----|------H

The migrate_pfn is just below a memory hole and the free scanner is beyond
the hole.  When isolate_migratepages started, it scans from migrate_pfn to
migrate_pfn+pageblock_nr_pages which is now in a memory hole.  It checks
pfn_valid() on the first PFN but then scans into the hole where there are
not necessarily valid struct pages.

This patch ensures that isolate_migratepages calls pfn_valid when
necessary.

Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

@raspberrypi raspberrypi referenced this issue May 12, 2012

Closed

JIRA SW-5991 #20

andatche pushed a commit to andatche/raspi-linux that referenced this issue May 29, 2012

hwmon: (coretemp) fix oops on cpu unplug
commit b704871 upstream.

coretemp tries to access core_data array beyond bounds on cpu unplug if
core id of the cpu if more than NUM_REAL_CORES-1.

BUG: unable to handle kernel NULL pointer dereference at 000000000000013c
IP: [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
PGD 673e5a067 PUD 66e9b3067 PMD 0
Oops: 0000 [#1] SMP
CPU 79
Modules linked in: sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf bnep bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter nf_conntrack_ipv4 nf_defrag_ipv4 ip6_tables xt_state nf_conntrack coretemp crc32c_intel asix tpm_tis pcspkr usbnet iTCO_wdt i2c_i801 microcode mii joydev tpm i2c_core iTCO_vendor_support tpm_bios i7core_edac igb ioatdma edac_core dca megaraid_sas [last unloaded: oprofile]

Pid: 3315, comm: set-cpus Tainted: G        W    3.4.0-rc5+ #2 QCI QSSC-S4R/QSSC-S4R
RIP: 0010:[<ffffffffa00159af>]  [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
RSP: 0018:ffff880472fb3d48  EFLAGS: 00010246
RAX: 0000000000000124 RBX: 0000000000000034 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: 0000000000000046 RDI: 0000000000000246
RBP: ffff880472fb3d88 R08: ffff88077fcd36c0 R09: 0000000000000001
R10: ffffffff8184bc48 R11: 0000000000000000 R12: ffff880273095800
R13: 0000000000000013 R14: ffff8802730a1810 R15: 0000000000000000
FS:  00007f694a20f720(0000) GS:ffff88077fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 000000000000013c CR3: 000000067209b000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process set-cpus (pid: 3315, threadinfo ffff880472fb2000, task ffff880471fa0000)
Stack:
 ffff880277b4c308 0000000000000003 ffff880472fb3d88 0000000000000005
 0000000000000034 00000000ffffffd1 ffffffff81cadc70 ffff880472fb3e14
 ffff880472fb3dc8 ffffffff8161f48d ffff880471fa0000 0000000000000034
Call Trace:
 [<ffffffff8161f48d>] notifier_call_chain+0x4d/0x70
 [<ffffffff8107f1be>] __raw_notifier_call_chain+0xe/0x10
 [<ffffffff81059d30>] __cpu_notify+0x20/0x40
 [<ffffffff815fa251>] _cpu_down+0x81/0x270
 [<ffffffff815fa477>] cpu_down+0x37/0x50
 [<ffffffff815fd6a3>] store_online+0x63/0xc0
 [<ffffffff813c7078>] dev_attr_store+0x18/0x30
 [<ffffffff811f02cf>] sysfs_write_file+0xef/0x170
 [<ffffffff81180443>] vfs_write+0xb3/0x180
 [<ffffffff8118076a>] sys_write+0x4a/0x90
 [<ffffffff816236a9>] system_call_fastpath+0x16/0x1b
Code: 48 c7 c7 94 60 01 a0 44 0f b7 ac 10 ac 00 00 00 31 c0 e8 41 b7 5f e1 41 83 c5 02 49 63 c5 49 8b 44 c4 10 48 85 c0 74 56 45 31 ff <39> 58 18 75 4e eb 1f 49 63 d7 4c 89 f7 48 89 45 c8 48 6b d2 28
RIP  [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
 RSP <ffff880472fb3d48>
CR2: 000000000000013c

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

ks8851: Fix mutex deadlock in ks8851_net_stop()
There is a potential deadlock scenario when the ks8851 driver
is removed. The interrupt handler schedules a workqueue which
acquires a mutex that ks8851_net_stop() also acquires before
flushing the workqueue. Previously lockdep wouldn't be able
to find this problem but now that it has the support we can
trigger this lockdep warning by rmmoding the driver after
an ifconfig up.

Fix the possible deadlock by disabling the interrupts in
the chip and then release the lock across the workqueue
flushing. The mutex is only there to proect the registers
anyway so this should be ok.

=======================================================
[ INFO: possible circular locking dependency detected ]
3.0.21-00021-g8b33780-dirty #2911
-------------------------------------------------------
rmmod/125 is trying to acquire lock:
 ((&ks->irq_work)){+.+...}, at: [<c019e0b8>] flush_work+0x0/0xac

but task is already holding lock:
 (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ks->lock){+.+...}:
       [<c01b89c8>] __lock_acquire+0x940/0x9f8
       [<c01b9058>] lock_acquire+0x10c/0x130
       [<c083dbec>] mutex_lock_nested+0x68/0x3dc
       [<bf00bd48>] ks8851_irq_work+0x24/0x46c [ks8851]
       [<c019c580>] process_one_work+0x2d8/0x518
       [<c019cb98>] worker_thread+0x220/0x3a0
       [<c01a2ad4>] kthread+0x88/0x94
       [<c0107008>] kernel_thread_exit+0x0/0x8

-> #0 ((&ks->irq_work)){+.+...}:
       [<c01b7984>] validate_chain+0x914/0x1018
       [<c01b89c8>] __lock_acquire+0x940/0x9f8
       [<c01b9058>] lock_acquire+0x10c/0x130
       [<c019e104>] flush_work+0x4c/0xac
       [<bf00b858>] ks8851_net_stop+0x6c/0x138 [ks8851]
       [<c06b209c>] __dev_close_many+0x98/0xcc
       [<c06b2174>] dev_close_many+0x68/0xd0
       [<c06b22ec>] rollback_registered_many+0xcc/0x2b8
       [<c06b2554>] rollback_registered+0x28/0x34
       [<c06b25b8>] unregister_netdevice_queue+0x58/0x7c
       [<c06b25f4>] unregister_netdev+0x18/0x20
       [<bf00c1f4>] ks8851_remove+0x64/0xb4 [ks8851]
       [<c049ddf0>] spi_drv_remove+0x18/0x1c
       [<c0468e98>] __device_release_driver+0x7c/0xbc
       [<c0468f64>] driver_detach+0x8c/0xb4
       [<c0467f00>] bus_remove_driver+0xb8/0xe8
       [<c01c1d20>] sys_delete_module+0x1e8/0x27c
       [<c0105ec0>] ret_fast_syscall+0x0/0x3c

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ks->lock);
                               lock((&ks->irq_work));
                               lock(&ks->lock);
  lock((&ks->irq_work));

 *** DEADLOCK ***

4 locks held by rmmod/125:
 #0:  (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f44>] driver_detach+0x6c/0xb4
 #1:  (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f50>] driver_detach+0x78/0xb4
 #2:  (rtnl_mutex){+.+.+.}, at: [<c06b25e8>] unregister_netdev+0xc/0x20
 #3:  (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

Konrad Rzeszutek Wilk
xen/enlighten: Disable MWAIT_LEAF so that acpi-pad won't be loaded.
There are exactly four users of __monitor and __mwait:

 - cstate.c (which allows acpi_processor_ffh_cstate_enter to be called
   when the cpuidle API drivers are used. However patch
   "cpuidle: replace xen access to x86 pm_idle and default_idle"
   provides a mechanism to disable the cpuidle and use safe_halt.
 - smpboot (which allows mwait_play_dead to be called). However
   safe_halt is always used so we skip that.
 - intel_idle (same deal as above).
 - acpi_pad.c. This the one that we do not want to run as we
   will hit the below crash.

Why do we want to expose MWAIT_LEAF in the first place?
We want it for the xen-acpi-processor driver - which uploads
C-states to the hypervisor. If MWAIT_LEAF is set, the cstate.c
sets the proper address in the C-states so that the hypervisor
can benefit from using the MWAIT functionality. And that is
the sole reason for using it.

Without this patch, if a module performs mwait or monitor we
get this:

invalid opcode: 0000 [#1] SMP
CPU 2
.. snip..
Pid: 5036, comm: insmod Tainted: G           O 3.4.0-rc2upstream-dirty #2 Intel Corporation S2600CP/S2600CP
RIP: e030:[<ffffffffa000a017>]  [<ffffffffa000a017>] mwait_check_init+0x17/0x1000 [mwait_check]
RSP: e02b:ffff8801c298bf18  EFLAGS: 00010282
RAX: ffff8801c298a010 RBX: ffffffffa03b2000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8801c29800d8 RDI: ffff8801ff097200
RBP: ffff8801c298bf18 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffffffa000a000 R14: 0000005148db7294 R15: 0000000000000003
FS:  00007fbb364f2700(0000) GS:ffff8801ff08c000(0000) knlGS:0000000000000000
CS:  e033 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 000000000179f038 CR3: 00000001c9469000 CR4: 0000000000002660
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process insmod (pid: 5036, threadinfo ffff8801c298a000, task ffff8801c29cd7e0)
Stack:
 ffff8801c298bf48 ffffffff81002124 ffffffffa03b2000 00000000000081fd
 000000000178f010 000000000178f030 ffff8801c298bf78 ffffffff810c41e6
 00007fff3fb30db9 00007fff3fb30db9 00000000000081fd 0000000000010000
Call Trace:
 [<ffffffff81002124>] do_one_initcall+0x124/0x170
 [<ffffffff810c41e6>] sys_init_module+0xc6/0x220
 [<ffffffff815b15b9>] system_call_fastpath+0x16/0x1b
Code: <0f> 01 c8 31 c0 0f 01 c9 c9 c3 00 00 00 00 00 00 00 00 00 00 00 00
RIP  [<ffffffffa000a017>] mwait_check_init+0x17/0x1000 [mwait_check]
 RSP <ffff8801c298bf18>
---[ end trace 16582fc8a3d1e29a ]---
Kernel panic - not syncing: Fatal exception

With this module (which is what acpi_pad.c would hit):

MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>");
MODULE_DESCRIPTION("mwait_check_and_back");
MODULE_LICENSE("GPL");
MODULE_VERSION();

static int __init mwait_check_init(void)
{
	__monitor((void *)&current_thread_info()->flags, 0, 0);
	__mwait(0, 0);
	return 0;
}
static void __exit mwait_check_exit(void)
{
}
module_init(mwait_check_init);
module_exit(mwait_check_exit);

Reported-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

Kirill A. Shutemov Guenter Roeck
hwmon: (coretemp) fix oops on cpu unplug
coretemp tries to access core_data array beyond bounds on cpu unplug if
core id of the cpu if more than NUM_REAL_CORES-1.

BUG: unable to handle kernel NULL pointer dereference at 000000000000013c
IP: [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
PGD 673e5a067 PUD 66e9b3067 PMD 0
Oops: 0000 [#1] SMP
CPU 79
Modules linked in: sunrpc cpufreq_ondemand acpi_cpufreq freq_table mperf bnep bluetooth rfkill ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter nf_conntrack_ipv4 nf_defrag_ipv4 ip6_tables xt_state nf_conntrack coretemp crc32c_intel asix tpm_tis pcspkr usbnet iTCO_wdt i2c_i801 microcode mii joydev tpm i2c_core iTCO_vendor_support tpm_bios i7core_edac igb ioatdma edac_core dca megaraid_sas [last unloaded: oprofile]

Pid: 3315, comm: set-cpus Tainted: G        W    3.4.0-rc5+ #2 QCI QSSC-S4R/QSSC-S4R
RIP: 0010:[<ffffffffa00159af>]  [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
RSP: 0018:ffff880472fb3d48  EFLAGS: 00010246
RAX: 0000000000000124 RBX: 0000000000000034 RCX: 00000000ffffffff
RDX: 0000000000000000 RSI: 0000000000000046 RDI: 0000000000000246
RBP: ffff880472fb3d88 R08: ffff88077fcd36c0 R09: 0000000000000001
R10: ffffffff8184bc48 R11: 0000000000000000 R12: ffff880273095800
R13: 0000000000000013 R14: ffff8802730a1810 R15: 0000000000000000
FS:  00007f694a20f720(0000) GS:ffff88077fcc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 000000000000013c CR3: 000000067209b000 CR4: 00000000000007e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process set-cpus (pid: 3315, threadinfo ffff880472fb2000, task ffff880471fa0000)
Stack:
 ffff880277b4c308 0000000000000003 ffff880472fb3d88 0000000000000005
 0000000000000034 00000000ffffffd1 ffffffff81cadc70 ffff880472fb3e14
 ffff880472fb3dc8 ffffffff8161f48d ffff880471fa0000 0000000000000034
Call Trace:
 [<ffffffff8161f48d>] notifier_call_chain+0x4d/0x70
 [<ffffffff8107f1be>] __raw_notifier_call_chain+0xe/0x10
 [<ffffffff81059d30>] __cpu_notify+0x20/0x40
 [<ffffffff815fa251>] _cpu_down+0x81/0x270
 [<ffffffff815fa477>] cpu_down+0x37/0x50
 [<ffffffff815fd6a3>] store_online+0x63/0xc0
 [<ffffffff813c7078>] dev_attr_store+0x18/0x30
 [<ffffffff811f02cf>] sysfs_write_file+0xef/0x170
 [<ffffffff81180443>] vfs_write+0xb3/0x180
 [<ffffffff8118076a>] sys_write+0x4a/0x90
 [<ffffffff816236a9>] system_call_fastpath+0x16/0x1b
Code: 48 c7 c7 94 60 01 a0 44 0f b7 ac 10 ac 00 00 00 31 c0 e8 41 b7 5f e1 41 83 c5 02 49 63 c5 49 8b 44 c4 10 48 85 c0 74 56 45 31 ff <39> 58 18 75 4e eb 1f 49 63 d7 4c 89 f7 48 89 45 c8 48 6b d2 28
RIP  [<ffffffffa00159af>] coretemp_cpu_callback+0x93/0x1ba [coretemp]
 RSP <ffff880472fb3d48>
CR2: 000000000000013c

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

James Bottomley James Bottomley
[PARISC] fix PA1.1 oops on boot
All PA1.1 systems have been oopsing on boot since

commit f311847
Author: James Bottomley <James.Bottomley@HansenPartnership.com>
Date:   Wed Dec 22 10:22:11 2010 -0600

    parisc: flush pages through tmpalias space

because a PA2.0 instruction was accidentally introduced into the PA1.1 TLB
insertion interruption path when it was consolidated with the do_alias macro.
Fix the do_alias macro only to use PA2.0 instructions if compiled for 64 bit.
Cc: stable@vger.kernel.org  #2.6.39+
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

John David Anglin James Bottomley
[PARISC] fix crash in flush_icache_page_asm on PA1.1
As pointed out by serveral people, PA1.1 only has a type 26 instruction
meaning that the space register must be explicitly encoded.  Not giving an
explicit space means that the compiler uses the type 24 version which is PA2.0
only resulting in an illegal instruction crash.

This regression was caused by

    commit f311847
    Author: James Bottomley <James.Bottomley@HansenPartnership.com>
    Date:   Wed Dec 22 10:22:11 2010 -0600

        parisc: flush pages through tmpalias space

Reported-by: Helge Deller <deller@gmx.de>
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org	#2.6.39+
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

erique pushed a commit to erique/rpi_linux that referenced this issue Jul 16, 2012

mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race …
…condition

commit 26c1917 upstream.

When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 #1 [f06a9e2c] oops_end at c083d1c2
 #2 [f06a9e40] no_context at c0433ded
 #3 [f06a9e64] bad_area_nosemaphore at c043401a
 #4 [f06a9e6c] __do_page_fault at c0434493
 #5 [f06a9eec] do_page_fault at c083eb45
 #6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 #7 [f06a9f38] _spin_lock at c083bc14
 #8 [f06a9f44] sys_mincore at c0507b7d
 #9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012

cifs: when CONFIG_HIGHMEM is set, serialize the read/write kmaps
commit 3cf003c upstream.

Jian found that when he ran fsx on a 32 bit arch with a large wsize the
process and one of the bdi writeback kthreads would sometimes deadlock
with a stack trace like this:

crash> bt
PID: 2789   TASK: f02edaa0  CPU: 3   COMMAND: "fsx"
 #0 [eed63cbc] schedule at c083c5b3
 #1 [eed63d80] kmap_high at c0500ec8
 #2 [eed63db0] cifs_async_writev at f7fabcd7 [cifs]
 #3 [eed63df0] cifs_writepages at f7fb7f5c [cifs]
 #4 [eed63e50] do_writepages at c04f3e32
 #5 [eed63e54] __filemap_fdatawrite_range at c04e152a
 #6 [eed63ea4] filemap_fdatawrite at c04e1b3e
 #7 [eed63eb4] cifs_file_aio_write at f7fa111a [cifs]
 #8 [eed63ecc] do_sync_write at c052d202
 #9 [eed63f74] vfs_write at c052d4ee
#10 [eed63f94] sys_write at c052df4c
#11 [eed63fb0] ia32_sysenter_target at c0409a98
    EAX: 00000004  EBX: 00000003  ECX: abd73b73  EDX: 012a65c6
    DS:  007b      ESI: 012a65c6  ES:  007b      EDI: 00000000
    SS:  007b      ESP: bf8db178  EBP: bf8db1f8  GS:  0033
    CS:  0073      EIP: 40000424  ERR: 00000004  EFLAGS: 00000246

Each task would kmap part of its address array before getting stuck, but
not enough to actually issue the write.

This patch fixes this by serializing the marshal_iov operations for
async reads and writes. The idea here is to ensure that cifs
aggressively tries to populate a request before attempting to fulfill
another one. As soon as all of the pages are kmapped for a request, then
we can unlock and allow another one to proceed.

There's no need to do this serialization on non-CONFIG_HIGHMEM arches
however, so optimize all of this out when CONFIG_HIGHMEM isn't set.

Reported-by: Jian Li <jiali@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

popcornmix pushed a commit to popcornmix/linux that referenced this issue Aug 16, 2012

nfs: skip commit in releasepage if we're freeing memory for fs-relate…
…d reasons

commit 5cf02d0 upstream.

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

    PID: 2507   TASK: ffff88103691ab40  CPU: 14  COMMAND: "rpciod/14"
     #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
     #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
     #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
     #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
     #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
     #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
     #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
     #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
     #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
     #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
    #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
    #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
    #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
    #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
    #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
    #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
    #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
    #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
    #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
    #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
    #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
    #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
    #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
    #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
    #24 [ffff8810343bfee8] kthread at ffffffff8108dd96
    #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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popcornmix Aug 20, 2012

Collaborator

The kernel update to 3.2.27 should have solved this. Please reopen if you don't think this is fixed.

Collaborator

popcornmix commented Aug 20, 2012

The kernel update to 3.2.27 should have solved this. Please reopen if you don't think this is fixed.

@popcornmix popcornmix closed this Aug 20, 2012

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Bluetooth: Fix potential deadlock
We don't need to use the _sync variant in hci_conn_hold and
hci_conn_put to cancel conn->disc_work delayed work. This way
we avoid potential deadlocks like this one reported by lockdep.

======================================================
[ INFO: possible circular locking dependency detected ]
3.2.0+ #1 Not tainted
-------------------------------------------------------
kworker/u:1/17 is trying to acquire lock:
 (&hdev->lock){+.+.+.}, at: [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]

but task is already holding lock:
 ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 ((&(&conn->disc_work)->work)){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff81034ed1>] wait_on_work+0x3d/0xaa
       [<ffffffff81035b54>] __cancel_work_timer+0xac/0xef
       [<ffffffff81035ba4>] cancel_delayed_work_sync+0xd/0xf
       [<ffffffffa00554b0>] smp_chan_create+0xde/0xe6 [bluetooth]
       [<ffffffffa0056160>] smp_conn_security+0xa3/0x12d [bluetooth]
       [<ffffffffa0053640>] l2cap_connect_cfm+0x237/0x2e8 [bluetooth]
       [<ffffffffa004239c>] hci_proto_connect_cfm+0x2d/0x6f [bluetooth]
       [<ffffffffa0046ea5>] hci_event_packet+0x29d1/0x2d60 [bluetooth]
       [<ffffffffa003dde3>] hci_rx_work+0xd0/0x2e1 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

-> #1 (slock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}:
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e553a>] _raw_spin_lock_bh+0x36/0x6a
       [<ffffffff81244d56>] lock_sock_nested+0x24/0x7f
       [<ffffffffa004d96f>] lock_sock+0xb/0xd [bluetooth]
       [<ffffffffa0052906>] l2cap_chan_connect+0xa9/0x26f [bluetooth]
       [<ffffffffa00545f8>] l2cap_sock_connect+0xb3/0xff [bluetooth]
       [<ffffffff81243b48>] sys_connect+0x69/0x8a
       [<ffffffff812e6579>] system_call_fastpath+0x16/0x1b

-> #0 (&hdev->lock){+.+.+.}:
       [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
       [<ffffffff81057444>] lock_acquire+0x8a/0xa7
       [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
       [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
       [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
       [<ffffffff810357af>] process_one_work+0x178/0x2bf
       [<ffffffff81036178>] worker_thread+0xce/0x152
       [<ffffffff81039a03>] kthread+0x95/0x9d
       [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10

other info that might help us debug this:

Chain exists of:
  &hdev->lock --> slock-AF_BLUETOOTH-BTPROTO_L2CAP --> (&(&conn->disc_work)->work)

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock((&(&conn->disc_work)->work));
                               lock(slock-AF_BLUETOOTH-BTPROTO_L2CAP);
                               lock((&(&conn->disc_work)->work));
  lock(&hdev->lock);

 *** DEADLOCK ***

2 locks held by kworker/u:1/17:
 #0:  (hdev->name){.+.+.+}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf
 #1:  ((&(&conn->disc_work)->work)){+.+...}, at: [<ffffffff81035751>] process_one_work+0x11a/0x2bf

stack backtrace:
Pid: 17, comm: kworker/u:1 Not tainted 3.2.0+ #1
Call Trace:
 [<ffffffff812e06c6>] print_circular_bug+0x1f8/0x209
 [<ffffffff81056d06>] __lock_acquire+0xa80/0xd74
 [<ffffffff81021ef2>] ? arch_local_irq_restore+0x6/0xd
 [<ffffffff81022bc7>] ? vprintk+0x3f9/0x41e
 [<ffffffff81057444>] lock_acquire+0x8a/0xa7
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff812e3870>] __mutex_lock_common+0x48/0x38e
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff81190fd6>] ? __dynamic_pr_debug+0x6d/0x6f
 [<ffffffffa0041155>] ? hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff8105320f>] ? trace_hardirqs_off+0xd/0xf
 [<ffffffff812e3c75>] mutex_lock_nested+0x2a/0x31
 [<ffffffffa0041155>] hci_conn_timeout+0x62/0x158 [bluetooth]
 [<ffffffff810357af>] process_one_work+0x178/0x2bf
 [<ffffffff81035751>] ? process_one_work+0x11a/0x2bf
 [<ffffffff81055af3>] ? lock_acquired+0x1d0/0x1df
 [<ffffffffa00410f3>] ? hci_acl_disconn+0x65/0x65 [bluetooth]
 [<ffffffff81036178>] worker_thread+0xce/0x152
 [<ffffffff810407ed>] ? finish_task_switch+0x45/0xc5
 [<ffffffff810360aa>] ? manage_workers.isra.25+0x16a/0x16a
 [<ffffffff81039a03>] kthread+0x95/0x9d
 [<ffffffff812e7754>] kernel_thread_helper+0x4/0x10
 [<ffffffff812e5db4>] ? retint_restore_args+0x13/0x13
 [<ffffffff8103996e>] ? __init_kthread_worker+0x55/0x55
 [<ffffffff812e7750>] ? gs_change+0x13/0x13

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Reviewed-by: Ulisses Furquim <ulisses@profusion.mobi>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Luck, Tony H. Peter Anvin
x86: Remove some noise from boot log when starting cpus
Printing the "start_ip" for every secondary cpu is very noisy on a large
system - and doesn't add any value. Drop this message.

Console log before:
Booting Node   0, Processors  #1
smpboot cpu 1: start_ip = 96000
 #2
smpboot cpu 2: start_ip = 96000
 #3
smpboot cpu 3: start_ip = 96000
 #4
smpboot cpu 4: start_ip = 96000
       ...
 #31
smpboot cpu 31: start_ip = 96000
Brought up 32 CPUs

Console log after:
Booting Node   0, Processors  #1 #2 #3 #4 #5 #6 #7 Ok.
Booting Node   1, Processors  #8 #9 #10 #11 #12 #13 #14 #15 Ok.
Booting Node   0, Processors  #16 #17 #18 #19 #20 #21 #22 #23 Ok.
Booting Node   1, Processors  #24 #25 #26 #27 #28 #29 #30 #31
Brought up 32 CPUs

Acked-by: Borislav Petkov <bp@amd64.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/4f452eb42507460426@agluck-desktop.sc.intel.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

[SCSI] libsas: fix lifetime of SAS_HA_FROZEN
Until all sas_tasks are known to no longer be in-flight this flag gates late
completions from colliding with error handling.  However, it must be cleared
prior to the submission of scsi_send_eh_cmnd() requests, otherwise those
commands will never be completed correctly.

This was spotted by slub debug:
 =============================================================================
 BUG sas_task: Objects remaining on kmem_cache_close()
 -----------------------------------------------------------------------------

 INFO: Slab 0xffffea001f0eba00 objects=34 used=1 fp=0xffff8807c3aecb00 flags=0x8000000000004080
 Pid: 22919, comm: modprobe Not tainted 3.2.0-isci+ #2
 Call Trace:
  [<ffffffff810fcdcd>] slab_err+0xb0/0xd2
  [<ffffffff810e1c50>] ? free_percpu+0x31/0x117
  [<ffffffff81100122>] ? kzalloc+0x14/0x16
  [<ffffffff81100122>] ? kzalloc+0x14/0x16
  [<ffffffff81100486>] kmem_cache_destroy+0x11d/0x270
  [<ffffffffa0112bdc>] sas_class_exit+0x10/0x12 [libsas]
  [<ffffffff81078fba>] sys_delete_module+0x1c4/0x23c
  [<ffffffff814797ba>] ? sysret_check+0x2e/0x69
  [<ffffffff8126479e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
  [<ffffffff81479782>] system_call_fastpath+0x16/0x1b
 INFO: Object 0xffff8807c3aed280 @offset=21120
 INFO: Allocated in sas_alloc_task+0x22/0x90 [libsas] age=4615311 cpu=2 pid=12966
  __slab_alloc.clone.3+0x1d1/0x234
  kmem_cache_alloc+0x52/0x10d
  sas_alloc_task+0x22/0x90 [libsas]
  sas_queuecommand+0x20e/0x230 [libsas]
  scsi_send_eh_cmnd+0xd1/0x30c
  scsi_eh_try_stu+0x4f/0x6b
  scsi_eh_ready_devs+0xba/0x6ef
  sas_scsi_recover_host+0xa35/0xab1 [libsas]
  scsi_error_handler+0x14b/0x5fa
  kthread+0x9d/0xa5
  kernel_thread_helper+0x4/0x10

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Srivatsa S. Bhat Borislav Petkov
x86, mce: Fix rcu splat in drain_mce_log_buffer()
While booting, the following message is seen:

[   21.665087] ===============================
[   21.669439] [ INFO: suspicious RCU usage. ]
[   21.673798] 3.2.0-0.0.0.28.36b5ec9-default #2 Not tainted
[   21.681353] -------------------------------
[   21.685864] arch/x86/kernel/cpu/mcheck/mce.c:194 suspicious rcu_dereference_index_check() usage!
[   21.695013]
[   21.695014] other info that might help us debug this:
[   21.695016]
[   21.703488]
[   21.703489] rcu_scheduler_active = 1, debug_locks = 1
[   21.710426] 3 locks held by modprobe/2139:
[   21.714754]  #0:  (&__lockdep_no_validate__){......}, at: [<ffffffff8133afd3>] __driver_attach+0x53/0xa0
[   21.725020]  #1:
[   21.725323] ioatdma: Intel(R) QuickData Technology Driver 4.00
[   21.733206]  (&__lockdep_no_validate__){......}, at: [<ffffffff8133afe1>] __driver_attach+0x61/0xa0
[   21.743015]  #2:  (i7core_edac_lock){+.+.+.}, at: [<ffffffffa01cfa5f>] i7core_probe+0x1f/0x5c0 [i7core_edac]
[   21.753708]
[   21.753709] stack backtrace:
[   21.758429] Pid: 2139, comm: modprobe Not tainted 3.2.0-0.0.0.28.36b5ec9-default #2
[   21.768253] Call Trace:
[   21.770838]  [<ffffffff810977cd>] lockdep_rcu_suspicious+0xcd/0x100
[   21.777366]  [<ffffffff8101aa41>] drain_mcelog_buffer+0x191/0x1b0
[   21.783715]  [<ffffffff8101aa78>] mce_register_decode_chain+0x18/0x20
[   21.790430]  [<ffffffffa01cf8db>] i7core_register_mci+0x2fb/0x3e4 [i7core_edac]
[   21.798003]  [<ffffffffa01cfb14>] i7core_probe+0xd4/0x5c0 [i7core_edac]
[   21.804809]  [<ffffffff8129566b>] local_pci_probe+0x5b/0xe0
[   21.810631]  [<ffffffff812957c9>] __pci_device_probe+0xd9/0xe0
[   21.816650]  [<ffffffff813362e4>] ? get_device+0x14/0x20
[   21.822178]  [<ffffffff81296916>] pci_device_probe+0x36/0x60
[   21.828061]  [<ffffffff8133ac8a>] really_probe+0x7a/0x2b0
[   21.833676]  [<ffffffff8133af23>] driver_probe_device+0x63/0xc0
[   21.839868]  [<ffffffff8133b01b>] __driver_attach+0x9b/0xa0
[   21.845718]  [<ffffffff8133af80>] ? driver_probe_device+0xc0/0xc0
[   21.852027]  [<ffffffff81339168>] bus_for_each_dev+0x68/0x90
[   21.857876]  [<ffffffff8133aa3c>] driver_attach+0x1c/0x20
[   21.863462]  [<ffffffff8133a64d>] bus_add_driver+0x16d/0x2b0
[   21.869377]  [<ffffffff8133b6dc>] driver_register+0x7c/0x160
[   21.875220]  [<ffffffff81296bda>] __pci_register_driver+0x6a/0xf0
[   21.881494]  [<ffffffffa01fe000>] ? 0xffffffffa01fdfff
[   21.886846]  [<ffffffffa01fe047>] i7core_init+0x47/0x1000 [i7core_edac]
[   21.893737]  [<ffffffff810001ce>] do_one_initcall+0x3e/0x180
[   21.899670]  [<ffffffff810a9b95>] sys_init_module+0xc5/0x220
[   21.905542]  [<ffffffff8149bc39>] system_call_fastpath+0x16/0x1b

Fix this by using ACCESS_ONCE() instead of rcu_dereference_check_mce()
over mcelog.next. Since the access to each entry is controlled by the
->finished field, ACCESS_ONCE() should work just fine. An rcu_dereference
is unnecessary here.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

device.h: audit and cleanup users in main include dir
The <linux/device.h> header includes a lot of stuff, and
it in turn gets a lot of use just for the basic "struct device"
which appears so often.

Clean up the users as follows:

1) For those headers only needing "struct device" as a pointer
in fcn args, replace the include with exactly that.

2) For headers not really using anything from device.h, simply
delete the include altogether.

3) For headers relying on getting device.h implicitly before
being included themselves, now explicitly include device.h

4) For files in which doing #1 or #2 uncovers an implicit
dependency on some other header, fix by explicitly adding
the required header(s).

Any C files that were implicitly relying on device.h to be
present have already been dealt with in advance.

Total removals from #1 and #2: 51.  Total additions coming
from #3: 9.  Total other implicit dependencies from #4: 7.

As of 3.3-rc1, there were 110, so a net removal of 42 gives
about a 38% reduction in device.h presence in include/*

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Disintegrate asm/system.h for Blackfin [ver #2]
Disintegrate asm/system.h for Blackfin.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: uclinux-dist-devel@blackfin.uclinux.org
Signed-off-by: Bob Liu <lliubbo@gmail.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel…
…/git/lliubbo/blackfin

Pull blackfin updates from Bob Liu

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lliubbo/blackfin: (24 commits)
  blackfin: clean up string bfin_dma_5xx after rename.
  blackfin:dma: rename bfin_dma_5xx.c to bfin_dma.c
  bf548: ssm2602: Add ssm2602 platform data into bf548 ezkit board file.
  Blackfin: s/#if CONFIG/#ifdef CONFIG/
  Blackfin: pnav: delete duplicate linux/export.h include
  bf561: add ppi DLEN macro for 10bits to 16bits
  arch: blackfin: udpate defconfig
  Disintegrate asm/system.h for Blackfin [ver #2]
  arch/blackfin: don't generate random mac in bfin_get_ether_addr()
  Blackfin: wire up new process_vm syscalls
  blackfin: cleanup anomaly workarounds
  blackfin: update default defconfig
  blackfin: thread_info: add suspend flag
  bfin: add bfin_ad73311_machine platform device
  blackfin: bf537: stamp: update board file for 193x
  blackfin: kgdb: skip hardware watchpoint test
  bf548: add ppi interrupt mask and blanking clocks
  blackfin: bf561: forgot CSYNC in get_core_lock_noflush
  spi/bfin_spi: drop bits_per_word from client data
  blackfin: cplb-mpu: fix page mask table overflow
  ...

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Merge branch 'amba' of git://git.linaro.org/people/rmk/linux-arm
Pull #2 ARM updates from Russell King:
 "Further ARM AMBA primecell updates which aren't included directly in
  the previous commit.  I wanted to keep these separate as they're
  touching stuff outside arch/arm/."

* 'amba' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7362/1: AMBA: Add module_amba_driver() helper macro for amba_driver
  ARM: 7335/1: mach-u300: do away with MMC config files
  ARM: 7280/1: mmc: mmci: Cache MMCICLOCK and MMCIPOWER register
  ARM: 7309/1: realview: fix unconnected interrupts on EB11MP
  ARM: 7230/1: mmc: mmci: Fix PIO read for small SDIO packets
  ARM: 7227/1: mmc: mmci: Prepare for SDIO before setting up DMA job
  ARM: 7223/1: mmc: mmci: Fixup use of runtime PM and use autosuspend
  ARM: 7221/1: mmc: mmci: Change from using legacy suspend
  ARM: 7219/1: mmc: mmci: Change vdd_handler to a generic ios_handler
  ARM: 7218/1: mmc: mmci: Provide option to configure bus signal direction
  ARM: 7217/1: mmc: mmci: Put power register deviations in variant data
  ARM: 7216/1: mmc: mmci: Do not release spinlock in request_end
  ARM: 7215/1: mmc: mmci: Increase max_segs from 16 to 128

popcornmix pushed a commit that referenced this issue Oct 13, 2012

blackfin: fix cmpxchg build fails from system.h fallout
Commit 3bed8d6 ("Disintegrate asm/system.h for Blackfin [ver #2]")
introduced arch/blackfin/include/asm/cmpxchg.h but has it also including
the asm-generic one which causes this:

  CC      arch/blackfin/kernel/asm-offsets.s
  In file included from arch/blackfin/include/asm/cmpxchg.h:125:0,
                 from arch/blackfin/include/asm/atomic.h:10,
                 from include/linux/atomic.h:4,
                 from include/linux/spinlock.h:384,
                 from include/linux/seqlock.h:29,
                 from include/linux/time.h:8,
                 from include/linux/timex.h:56,
                 from include/linux/sched.h:57,
                 from arch/blackfin/kernel/asm-offsets.c:10:
  include/asm-generic/cmpxchg.h:24:15: error: redefinition of '__xchg'
  arch/blackfin/include/asm/cmpxchg.h:82:29: note: previous definition of '__xchg' was here
  make[2]: *** [arch/blackfin/kernel/asm-offsets.s] Error 1

It really only needs two simple defines from asm-generic, so just use
those instead.

Cc: Bob Liu <lliubbo@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

kobject: provide more diagnostic info for kobject_add_internal() fail…
…ures

1/ convert open-coded KERN_ERR+dump_stack() to WARN(), so that automated
   tools pick up this warning.

2/ include the 'child' and 'parent' kobject names.  This information was
   useful for tracking down the case where scsi invoked device_del() on a
   parent object and subsequently invoked device_add() on a child.  Now the
   warning looks like:

     kobject_add_internal failed for target8:0:16 (error: -2 parent: end_device-8:0:24)
     Pid: 2942, comm: scsi_scan_8 Not tainted 3.3.0-rc7-isci+ #2
     Call Trace:
      [<ffffffff8125e551>] kobject_add_internal+0x1c1/0x1f3
      [<ffffffff81075149>] ? trace_hardirqs_on+0xd/0xf
      [<ffffffff8125e659>] kobject_add_varg+0x41/0x50
      [<ffffffff8125e723>] kobject_add+0x64/0x66
      [<ffffffff8131124b>] device_add+0x12d/0x63a
      [<ffffffff8125e0ef>] ? kobject_put+0x4c/0x50
      [<ffffffff8132f370>] scsi_sysfs_add_sdev+0x4e/0x28a
      [<ffffffff8132dce3>] do_scan_async+0x9c/0x145

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

IB/uverbs: Lock SRQ / CQ / PD objects in a consistent order
Since XRC support was added, the uverbs code has locked SRQ, CQ and PD
objects needed during QP and SRQ creation in different orders
depending on the the code path.  This leads to the (at least
theoretical) possibility of deadlock, and triggers the lockdep splat
below.

Fix this by making sure we always lock the SRQ first, then CQs and
finally the PD.

    ======================================================
    [ INFO: possible circular locking dependency detected ]
    3.4.0-rc5+ #34 Not tainted
    -------------------------------------------------------
    ibv_srq_pingpon/2484 is trying to acquire lock:
     (SRQ-uobj){+++++.}, at: [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]

    but task is already holding lock:
     (CQ-uobj){+++++.}, at: [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]

    which lock already depends on the new lock.

    the existing dependency chain (in reverse order) is:

    -> #2 (CQ-uobj){+++++.}:
           [<ffffffff81070fd0>] lock_acquire+0xbf/0xfe
           [<ffffffff81384f28>] down_read+0x34/0x43
           [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]
           [<ffffffffa00af542>] idr_read_obj+0x9/0x19 [ib_uverbs]
           [<ffffffffa00b16c3>] ib_uverbs_create_qp+0x180/0x684 [ib_uverbs]
           [<ffffffffa00ae3dd>] ib_uverbs_write+0xb7/0xc2 [ib_uverbs]
           [<ffffffff810fe47f>] vfs_write+0xa7/0xee
           [<ffffffff810fe65f>] sys_write+0x45/0x69
           [<ffffffff8138cdf9>] system_call_fastpath+0x16/0x1b

    -> #1 (PD-uobj){++++++}:
           [<ffffffff81070fd0>] lock_acquire+0xbf/0xfe
           [<ffffffff81384f28>] down_read+0x34/0x43
           [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]
           [<ffffffffa00af542>] idr_read_obj+0x9/0x19 [ib_uverbs]
           [<ffffffffa00af8ad>] __uverbs_create_xsrq+0x96/0x386 [ib_uverbs]
           [<ffffffffa00b31b9>] ib_uverbs_detach_mcast+0x1cd/0x1e6 [ib_uverbs]
           [<ffffffffa00ae3dd>] ib_uverbs_write+0xb7/0xc2 [ib_uverbs]
           [<ffffffff810fe47f>] vfs_write+0xa7/0xee
           [<ffffffff810fe65f>] sys_write+0x45/0x69
           [<ffffffff8138cdf9>] system_call_fastpath+0x16/0x1b

    -> #0 (SRQ-uobj){+++++.}:
           [<ffffffff81070898>] __lock_acquire+0xa29/0xd06
           [<ffffffff81070fd0>] lock_acquire+0xbf/0xfe
           [<ffffffff81384f28>] down_read+0x34/0x43
           [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]
           [<ffffffffa00af542>] idr_read_obj+0x9/0x19 [ib_uverbs]
           [<ffffffffa00b1728>] ib_uverbs_create_qp+0x1e5/0x684 [ib_uverbs]
           [<ffffffffa00ae3dd>] ib_uverbs_write+0xb7/0xc2 [ib_uverbs]
           [<ffffffff810fe47f>] vfs_write+0xa7/0xee
           [<ffffffff810fe65f>] sys_write+0x45/0x69
           [<ffffffff8138cdf9>] system_call_fastpath+0x16/0x1b

    other info that might help us debug this:

    Chain exists of:
      SRQ-uobj --> PD-uobj --> CQ-uobj

     Possible unsafe locking scenario:

           CPU0                    CPU1
           ----                    ----
      lock(CQ-uobj);
                                   lock(PD-uobj);
                                   lock(CQ-uobj);
      lock(SRQ-uobj);

     *** DEADLOCK ***

    3 locks held by ibv_srq_pingpon/2484:
     #0:  (QP-uobj){+.+...}, at: [<ffffffffa00b162c>] ib_uverbs_create_qp+0xe9/0x684 [ib_uverbs]
     #1:  (PD-uobj){++++++}, at: [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]
     #2:  (CQ-uobj){+++++.}, at: [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]

    stack backtrace:
    Pid: 2484, comm: ibv_srq_pingpon Not tainted 3.4.0-rc5+ #34
    Call Trace:
     [<ffffffff8137eff0>] print_circular_bug+0x1f8/0x209
     [<ffffffff81070898>] __lock_acquire+0xa29/0xd06
     [<ffffffffa00af37c>] ? __idr_get_uobj+0x20/0x5e [ib_uverbs]
     [<ffffffffa00af51b>] ? idr_read_uobj+0x2f/0x4d [ib_uverbs]
     [<ffffffff81070fd0>] lock_acquire+0xbf/0xfe
     [<ffffffffa00af51b>] ? idr_read_uobj+0x2f/0x4d [ib_uverbs]
     [<ffffffff81070eee>] ? lock_release+0x166/0x189
     [<ffffffff81384f28>] down_read+0x34/0x43
     [<ffffffffa00af51b>] ? idr_read_uobj+0x2f/0x4d [ib_uverbs]
     [<ffffffffa00af51b>] idr_read_uobj+0x2f/0x4d [ib_uverbs]
     [<ffffffffa00af542>] idr_read_obj+0x9/0x19 [ib_uverbs]
     [<ffffffffa00b1728>] ib_uverbs_create_qp+0x1e5/0x684 [ib_uverbs]
     [<ffffffff81070fec>] ? lock_acquire+0xdb/0xfe
     [<ffffffff81070c09>] ? lock_release_non_nested+0x94/0x213
     [<ffffffff810d470f>] ? might_fault+0x40/0x90
     [<ffffffff810d470f>] ? might_fault+0x40/0x90
     [<ffffffffa00ae3dd>] ib_uverbs_write+0xb7/0xc2 [ib_uverbs]
     [<ffffffff810fe47f>] vfs_write+0xa7/0xee
     [<ffffffff810ff736>] ? fget_light+0x3b/0x99
     [<ffffffff810fe65f>] sys_write+0x45/0x69
     [<ffffffff8138cdf9>] system_call_fastpath+0x16/0x1b

Reported-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

RDMA/cma: Fix lockdep false positive recursive locking
The following lockdep problem was reported by Or Gerlitz <ogerlitz@mellanox.com>:

    [ INFO: possible recursive locking detected ]
    3.3.0-32035-g1b2649e-dirty #4 Not tainted
    ---------------------------------------------
    kworker/5:1/418 is trying to acquire lock:
     (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0138a41>] rdma_destroy_i    d+0x33/0x1f0 [rdma_cm]

    but task is already holding lock:
     (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disable_ca    llback+0x24/0x45 [rdma_cm]

    other info that might help us debug this:
     Possible unsafe locking scenario:

           CPU0
           ----
      lock(&id_priv->handler_mutex);
      lock(&id_priv->handler_mutex);

     *** DEADLOCK ***

     May be due to missing lock nesting notation

    3 locks held by kworker/5:1/418:
     #0:  (ib_cm){.+.+.+}, at: [<ffffffff81042ac1>] process_one_work+0x210/0x4a    6
     #1:  ((&(&work->work)->work)){+.+.+.}, at: [<ffffffff81042ac1>] process_on    e_work+0x210/0x4a6
     #2:  (&id_priv->handler_mutex){+.+.+.}, at: [<ffffffffa0135130>] cma_disab    le_callback+0x24/0x45 [rdma_cm]

    stack backtrace:
    Pid: 418, comm: kworker/5:1 Not tainted 3.3.0-32035-g1b2649e-dirty #4
    Call Trace:
     [<ffffffff8102b0fb>] ? console_unlock+0x1f4/0x204
     [<ffffffff81068771>] __lock_acquire+0x16b5/0x174e
     [<ffffffff8106461f>] ? save_trace+0x3f/0xb3
     [<ffffffff810688fa>] lock_acquire+0xf0/0x116
     [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffff81364351>] mutex_lock_nested+0x64/0x2ce
     [<ffffffffa0138a41>] ? rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155
     [<ffffffff81065abc>] ? trace_hardirqs_on+0xd/0xf
     [<ffffffffa0138a41>] rdma_destroy_id+0x33/0x1f0 [rdma_cm]
     [<ffffffffa0139c02>] cma_req_handler+0x418/0x644 [rdma_cm]
     [<ffffffffa012ee88>] cm_process_work+0x32/0x119 [ib_cm]
     [<ffffffffa0130299>] cm_req_handler+0x928/0x982 [ib_cm]
     [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm]
     [<ffffffffa0130326>] cm_work_handler+0x33/0xfe5 [ib_cm]
     [<ffffffff81065a78>] ? trace_hardirqs_on_caller+0x11e/0x155
     [<ffffffffa01302f3>] ? cm_req_handler+0x982/0x982 [ib_cm]
     [<ffffffff81042b6e>] process_one_work+0x2bd/0x4a6
     [<ffffffff81042ac1>] ? process_one_work+0x210/0x4a6
     [<ffffffff813669f3>] ? _raw_spin_unlock_irq+0x2b/0x40
     [<ffffffff8104316e>] worker_thread+0x1d6/0x350
     [<ffffffff81042f98>] ? rescuer_thread+0x241/0x241
     [<ffffffff81046a32>] kthread+0x84/0x8c
     [<ffffffff8136e854>] kernel_thread_helper+0x4/0x10
     [<ffffffff81366d59>] ? retint_restore_args+0xe/0xe
     [<ffffffff810469ae>] ? __init_kthread_worker+0x56/0x56
     [<ffffffff8136e850>] ? gs_change+0xb/0xb

The actual locking is fine, since we're dealing with different locks,
but from the same lock class.  cma_disable_callback() acquires the
listening id mutex, whereas rdma_destroy_id() acquires the mutex for
the new connection id.  To fix this, delay the call to
rdma_destroy_id() until we've released the listening id mutex.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

popcornmix pushed a commit that referenced this issue Oct 13, 2012

Ben Myers
xfs: protect xfs_sync_worker with s_umount semaphore
xfs_sync_worker checks the MS_ACTIVE flag in s_flags to avoid doing
work during mount and unmount.  This flag can be cleared by unmount
after the xfs_sync_worker checks it but before the work is completed.
The has caused crashes in the completion handler for the dummy
transaction commited by xfs_sync_worker:

PID: 27544  TASK: ffff88013544e040  CPU: 3   COMMAND: "kworker/3:0"
 #0 [ffff88016fdff930] machine_kexec at ffffffff810244e9
 #1 [ffff88016fdff9a0] crash_kexec at ffffffff8108d053
 #2 [ffff88016fdffa70] oops_end at ffffffff813ad1b8
 #3 [ffff88016fdffaa0] no_context at ffffffff8102bd48
 #4 [ffff88016fdffaf0] __bad_area_nosemaphore at ffffffff8102c04d
 #5 [ffff88016fdffb40] bad_area_nosemaphore at ffffffff8102c12e
 #6 [ffff88016fdffb50] do_page_fault at ffffffff813afaee
 #7 [ffff88016fdffc60] page_fault at ffffffff813ac635
    [exception RIP: xlog_get_lowest_lsn+0x30]
    RIP: ffffffffa04a9910  RSP: ffff88016fdffd10  RFLAGS: 00010246
    RAX: ffffc90014e48000  RBX: ffff88014d879980  RCX: ffff88014d879980
    RDX: ffff8802214ee4c0  RSI: 0000000000000000  RDI: 0000000000000000
    RBP: ffff88016fdffd10   R8: ffff88014d879a80   R9: 0000000000000000
    R10: 0000000000000001  R11: 0000000000000000  R12: ffff8802214ee400
    R13: ffff88014d879980  R14: 0000000000000000  R15: ffff88022fd96605
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #8 [ffff88016fdffd18] xlog_state_do_callback at ffffffffa04aa186 [xfs]
 #9 [ffff88016fdffd98] xlog_state_done_syncing at ffffffffa04aa568 [xfs]

Protect xfs_sync_worker by using the s_umount semaphore at the read
level to provide exclusion with unmount while work is progressing.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

popcornmix pushed a commit that referenced this issue Jul 20, 2018

cifs: Fix slab-out-of-bounds in send_set_info() on SMB2 ACE setting
commit f46ecbd upstream.

A "small" CIFS buffer is not big enough in general to hold a
setacl request for SMB2, and we end up overflowing the buffer in
send_set_info(). For instance:

 # mount.cifs //127.0.0.1/test /mnt/test -o username=test,password=test,nounix,cifsacl
 # touch /mnt/test/acltest
 # getcifsacl /mnt/test/acltest
 REVISION:0x1
 CONTROL:0x9004
 OWNER:S-1-5-21-2926364953-924364008-418108241-1000
 GROUP:S-1-22-2-1001
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-1-0:ALLOWED/0x0/R
 # setcifsacl -a "ACL:S-1-22-2-1004:ALLOWED/0x0/R" /mnt/test/acltest

this setacl will cause the following KASAN splat:

[  330.777927] BUG: KASAN: slab-out-of-bounds in send_set_info+0x4dd/0xc20 [cifs]
[  330.779696] Write of size 696 at addr ffff88010d5e2860 by task setcifsacl/1012

[  330.781882] CPU: 1 PID: 1012 Comm: setcifsacl Not tainted 4.18.0-rc2+ #2
[  330.783140] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  330.784395] Call Trace:
[  330.784789]  dump_stack+0xc2/0x16b
[  330.786777]  print_address_description+0x6a/0x270
[  330.787520]  kasan_report+0x258/0x380
[  330.788845]  memcpy+0x34/0x50
[  330.789369]  send_set_info+0x4dd/0xc20 [cifs]
[  330.799511]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.801395]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.830888]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.840367]  __vfs_setxattr+0x84/0xb0
[  330.842060]  __vfs_setxattr_noperm+0xe6/0x370
[  330.843848]  vfs_setxattr+0xc2/0xd0
[  330.845519]  setxattr+0x258/0x320
[  330.859211]  path_setxattr+0x15b/0x1b0
[  330.864392]  __x64_sys_setxattr+0xc0/0x160
[  330.866133]  do_syscall_64+0x14e/0x4b0
[  330.876631]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  330.878503] RIP: 0033:0x7ff2e507db0a
[  330.880151] Code: 48 8b 0d 89 93 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 bc 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 56 93 2c 00 f7 d8 64 89 01 48
[  330.885358] RSP: 002b:00007ffdc4903c18 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
[  330.887733] RAX: ffffffffffffffda RBX: 000055d1170de140 RCX: 00007ff2e507db0a
[  330.890067] RDX: 000055d1170de7d0 RSI: 000055d115b39184 RDI: 00007ffdc4904818
[  330.892410] RBP: 0000000000000001 R08: 0000000000000000 R09: 000055d1170de7e4
[  330.894785] R10: 00000000000002b8 R11: 0000000000000246 R12: 0000000000000007
[  330.897148] R13: 000055d1170de0c0 R14: 0000000000000008 R15: 000055d1170de550

[  330.901057] Allocated by task 1012:
[  330.902888]  kasan_kmalloc+0xa0/0xd0
[  330.904714]  kmem_cache_alloc+0xc8/0x1d0
[  330.906615]  mempool_alloc+0x11e/0x380
[  330.908496]  cifs_small_buf_get+0x35/0x60 [cifs]
[  330.910510]  smb2_plain_req_init+0x4a/0xd60 [cifs]
[  330.912551]  send_set_info+0x198/0xc20 [cifs]
[  330.914535]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.916465]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.918453]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.920426]  __vfs_setxattr+0x84/0xb0
[  330.922284]  __vfs_setxattr_noperm+0xe6/0x370
[  330.924213]  vfs_setxattr+0xc2/0xd0
[  330.926008]  setxattr+0x258/0x320
[  330.927762]  path_setxattr+0x15b/0x1b0
[  330.929592]  __x64_sys_setxattr+0xc0/0x160
[  330.931459]  do_syscall_64+0x14e/0x4b0
[  330.933314]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  330.936843] Freed by task 0:
[  330.938588] (stack is not available)

[  330.941886] The buggy address belongs to the object at ffff88010d5e2800
 which belongs to the cache cifs_small_rq of size 448
[  330.946362] The buggy address is located 96 bytes inside of
 448-byte region [ffff88010d5e2800, ffff88010d5e29c0)
[  330.950722] The buggy address belongs to the page:
[  330.952789] page:ffffea0004357880 count:1 mapcount:0 mapping:ffff880108fdca80 index:0x0 compound_mapcount: 0
[  330.955665] flags: 0x17ffffc0008100(slab|head)
[  330.957760] raw: 0017ffffc0008100 dead000000000100 dead000000000200 ffff880108fdca80
[  330.960356] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
[  330.963005] page dumped because: kasan: bad access detected

[  330.967039] Memory state around the buggy address:
[  330.969255]  ffff88010d5e2880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.971833]  ffff88010d5e2900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.974397] >ffff88010d5e2980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
[  330.976956]                                            ^
[  330.979226]  ffff88010d5e2a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.981755]  ffff88010d5e2a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.984225] ==================================================================

Fix this by allocating a regular CIFS buffer in
smb2_plain_req_init() if the request command is SMB2_SET_INFO.

Reported-by: Jianhong Yin <jiyin@redhat.com>
Fixes: 366ed84 ("cifs: Use smb 2 - 3 and cifsacl mount options setacl function")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-and-tested-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 20, 2018

MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()
commit b63e132 upstream.

The current MIPS implementation of arch_trigger_cpumask_backtrace() is
broken because it attempts to use synchronous IPIs despite the fact that
it may be run with interrupts disabled.

This means that when arch_trigger_cpumask_backtrace() is invoked, for
example by the RCU CPU stall watchdog, we may:

  - Deadlock due to use of synchronous IPIs with interrupts disabled,
    causing the CPU that's attempting to generate the backtrace output
    to hang itself.

  - Not succeed in generating the desired output from remote CPUs.

  - Produce warnings about this from smp_call_function_many(), for
    example:

    [42760.526910] INFO: rcu_sched detected stalls on CPUs/tasks:
    [42760.535755]  0-...!: (1 GPs behind) idle=ade/140000000000000/0 softirq=526944/526945 fqs=0
    [42760.547874]  1-...!: (0 ticks this GP) idle=e4a/140000000000000/0 softirq=547885/547885 fqs=0
    [42760.559869]  (detected by 2, t=2162 jiffies, g=266689, c=266688, q=33)
    [42760.568927] ------------[ cut here ]------------
    [42760.576146] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:416 smp_call_function_many+0x88/0x20c
    [42760.587839] Modules linked in:
    [42760.593152] CPU: 2 PID: 1216 Comm: sh Not tainted 4.15.4-00373-gee058bb4d0c2 #2
    [42760.603767] Stack : 8e09bd20 8e09bd20 8e09bd20 fffffff0 00000007 00000006 00000000 8e09bca8
    [42760.616937]         95b2b379 95b2b379 807a0080 00000007 81944518 0000018a 00000032 00000000
    [42760.630095]         00000000 00000030 80000000 00000000 806eca74 00000009 8017e2b8 000001a0
    [42760.643169]         00000000 00000002 00000000 8e09baa4 00000008 808b8008 86d69080 8e09bca0
    [42760.656282]         8e09ad50 805e20aa 00000000 00000000 00000000 8017e2b8 00000009 801070ca
    [42760.669424]         ...
    [42760.673919] Call Trace:
    [42760.678672] [<27fde568>] show_stack+0x70/0xf0
    [42760.685417] [<84751641>] dump_stack+0xaa/0xd0
    [42760.692188] [<699d671c>] __warn+0x80/0x92
    [42760.698549] [<68915d41>] warn_slowpath_null+0x28/0x36
    [42760.705912] [<f7c76c1c>] smp_call_function_many+0x88/0x20c
    [42760.713696] [<6bbdfc2a>] arch_trigger_cpumask_backtrace+0x30/0x4a
    [42760.722216] [<f845bd33>] rcu_dump_cpu_stacks+0x6a/0x98
    [42760.729580] [<796e7629>] rcu_check_callbacks+0x672/0x6ac
    [42760.737476] [<059b3b43>] update_process_times+0x18/0x34
    [42760.744981] [<6eb94941>] tick_sched_handle.isra.5+0x26/0x38
    [42760.752793] [<478d3d70>] tick_sched_timer+0x1c/0x50
    [42760.759882] [<e56ea39f>] __hrtimer_run_queues+0xc6/0x226
    [42760.767418] [<e88bbcae>] hrtimer_interrupt+0x88/0x19a
    [42760.775031] [<6765a19e>] gic_compare_interrupt+0x2e/0x3a
    [42760.782761] [<0558bf5f>] handle_percpu_devid_irq+0x78/0x168
    [42760.790795] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
    [42760.798117] [<1b6d462c>] gic_handle_local_int+0x38/0x86
    [42760.805545] [<b2ada1c7>] gic_irq_dispatch+0xa/0x14
    [42760.812534] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
    [42760.820086] [<c7521934>] do_IRQ+0x16/0x20
    [42760.826274] [<9aef3ce6>] plat_irq_dispatch+0x62/0x94
    [42760.833458] [<6a94b53c>] except_vec_vi_end+0x70/0x78
    [42760.840655] [<22284043>] smp_call_function_many+0x1ba/0x20c
    [42760.848501] [<54022b58>] smp_call_function+0x1e/0x2c
    [42760.855693] [<ab9fc705>] flush_tlb_mm+0x2a/0x98
    [42760.862730] [<0844cdd0>] tlb_flush_mmu+0x1c/0x44
    [42760.869628] [<cb259b74>] arch_tlb_finish_mmu+0x26/0x3e
    [42760.877021] [<1aeaaf74>] tlb_finish_mmu+0x18/0x66
    [42760.883907] [<b3fce717>] exit_mmap+0x76/0xea
    [42760.890428] [<c4c8a2f6>] mmput+0x80/0x11a
    [42760.896632] [<a41a08f4>] do_exit+0x1f4/0x80c
    [42760.903158] [<ee01cef6>] do_group_exit+0x20/0x7e
    [42760.909990] [<13fa8d54>] __wake_up_parent+0x0/0x1e
    [42760.917045] [<46cf89d0>] smp_call_function_many+0x1a2/0x20c
    [42760.924893] [<8c21a93b>] syscall_common+0x14/0x1c
    [42760.931765] ---[ end trace 02aa09da9dc52a60 ]---
    [42760.938342] ------------[ cut here ]------------
    [42760.945311] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:291 smp_call_function_single+0xee/0xf8
    ...

This patch switches MIPS' arch_trigger_cpumask_backtrace() to use async
IPIs & smp_call_function_single_async() in order to resolve this
problem. We ensure use of the pre-allocated call_single_data_t
structures is serialized by maintaining a cpumask indicating that
they're busy, and refusing to attempt to send an IPI when a CPU's bit is
set in this mask. This should only happen if a CPU hasn't responded to a
previous backtrace IPI - ie. if it's hung - and we print a warning to
the console in this case.

I've marked this for stable branches as far back as v4.9, to which it
applies cleanly. Strictly speaking the faulty MIPS implementation can be
traced further back to commit 856839b ("MIPS: Add
arch_trigger_all_cpu_backtrace() function") in v3.19, but kernel
versions v3.19 through v4.8 will require further work to backport due to
the rework performed in commit 9a01c3e ("nmi_backtrace: add more
trigger_*_cpu_backtrace() methods").

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19597/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # v4.9+
Fixes: 856839b ("MIPS: Add arch_trigger_all_cpu_backtrace() function")
Fixes: 9a01c3e ("nmi_backtrace: add more trigger_*_cpu_backtrace() methods")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 20, 2018

f2fs: avoid bug_on on corrupted inode
commit 5d64600 upstream.

syzbot has tested the proposed patch but the reproducer still triggered crash:
kernel BUG at fs/f2fs/inode.c:LINE!

F2FS-fs (loop1): invalid crc value
F2FS-fs (loop5): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop5): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop5): invalid crc value
------------[ cut here ]------------
kernel BUG at fs/f2fs/inode.c:238!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4886 Comm: syz-executor1 Not tainted 4.17.0-rc1+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_read_inode fs/f2fs/inode.c:238 [inline]
RIP: 0010:f2fs_iget+0x3307/0x3ca0 fs/f2fs/inode.c:313
RSP: 0018:ffff8801c44a70e8 EFLAGS: 00010293
RAX: ffff8801ce208040 RBX: ffff8801b3621080 RCX: ffffffff82eace18
F2FS-fs (loop2): Magic Mismatch, valid(0xf2f52010) - read(0x0)
RDX: 0000000000000000 RSI: ffffffff82eaf047 RDI: 0000000000000007
RBP: ffff8801c44a7410 R08: ffff8801ce208040 R09: ffffed0039ee4176
R10: ffffed0039ee4176 R11: ffff8801cf720bb7 R12: ffff8801c0efa000
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f753aa9d700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
------------[ cut here ]------------
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kernel BUG at fs/f2fs/inode.c:238!
CR2: 0000000001b03018 CR3: 00000001c8b74000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 f2fs_fill_super+0x4377/0x7bf0 fs/f2fs/super.c:2842
 mount_bdev+0x30c/0x3e0 fs/super.c:1165
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 __do_sys_mount fs/namespace.c:3077 [inline]
 __se_sys_mount fs/namespace.c:3074 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457daa
RSP: 002b:00007f753aa9cba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 0000000000457daa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f753aa9cbf0
RBP: 0000000000000064 R08: 0000000020016a00 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000064 R14: 00000000006fcb80 R15: 0000000000000000
RIP: do_read_inode fs/f2fs/inode.c:238 [inline] RSP: ffff8801c44a70e8
RIP: f2fs_iget+0x3307/0x3ca0 fs/f2fs/inode.c:313 RSP: ffff8801c44a70e8
invalid opcode: 0000 [#2] SMP KASAN
---[ end trace 1cbcbec2156680bc ]---

Reported-and-tested-by: syzbot+41a1b341571f0952badb@syzkaller.appspotmail.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 25, 2018

qmi_wwan: add support for the Dell Wireless 5821e module
[ Upstream commit e7e197e ]

This module exposes two USB configurations: a QMI+AT capable setup on
USB config #1 and a MBIM capable setup on USB config #2.

By default the kernel will choose the MBIM capable configuration as
long as the cdc_mbim driver is available. This patch adds support for
the QMI port in the secondary configuration.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 25, 2018

KEYS: DNS: fix parsing multiple options
commit c604cb7 upstream.

My recent fix for dns_resolver_preparse() printing very long strings was
incomplete, as shown by syzbot which still managed to hit the
WARN_ONCE() in set_precision() by adding a crafted "dns_resolver" key:

    precision 50001 too large
    WARNING: CPU: 7 PID: 864 at lib/vsprintf.c:2164 vsnprintf+0x48a/0x5a0

The bug this time isn't just a printing bug, but also a logical error
when multiple options ("#"-separated strings) are given in the key
payload.  Specifically, when separating an option string into name and
value, if there is no value then the name is incorrectly considered to
end at the end of the key payload, rather than the end of the current
option.  This bypasses validation of the option length, and also means
that specifying multiple options is broken -- which presumably has gone
unnoticed as there is currently only one valid option anyway.

A similar problem also applied to option values, as the kstrtoul() when
parsing the "dnserror" option will read past the end of the current
option and into the next option.

Fix these bugs by correctly computing the length of the option name and
by copying the option value, null-terminated, into a temporary buffer.

Reproducer for the WARN_ONCE() that syzbot hit:

    perl -e 'print "#A#", "\0" x 50000' | keyctl padd dns_resolver desc @s

Reproducer for "dnserror" option being parsed incorrectly (expected
behavior is to fail when seeing the unknown option "foo", actual
behavior was to read the dnserror value as "1#foo" and fail there):

    perl -e 'print "#dnserror=1#foo\0"' | keyctl padd dns_resolver desc @s

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 4a2d789 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 25, 2018

scsi: qla2xxx: Fix NULL pointer dereference for fcport search
commit 36eb8ff672faee83ccce60c191f0fef07c6adce6 upstream.

Crash dump shows following instructions

crash> bt
PID: 0      TASK: ffffffffbe412480  CPU: 0   COMMAND: "swapper/0"
 #0 [ffff891ee0003868] machine_kexec at ffffffffbd063ef1
 #1 [ffff891ee00038c8] __crash_kexec at ffffffffbd12b6f2
 #2 [ffff891ee0003998] crash_kexec at ffffffffbd12c84c
 #3 [ffff891ee00039b8] oops_end at ffffffffbd030f0a
 #4 [ffff891ee00039e0] no_context at ffffffffbd074643
 #5 [ffff891ee0003a40] __bad_area_nosemaphore at ffffffffbd07496e
 #6 [ffff891ee0003a90] bad_area_nosemaphore at ffffffffbd074a64
 #7 [ffff891ee0003aa0] __do_page_fault at ffffffffbd074b0a
 #8 [ffff891ee0003b18] do_page_fault at ffffffffbd074fc8
 #9 [ffff891ee0003b50] page_fault at ffffffffbda01925
    [exception RIP: qlt_schedule_sess_for_deletion+15]
    RIP: ffffffffc02e526f  RSP: ffff891ee0003c08  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: 0000000000000000  RCX: ffffffffc0307847
    RDX: 00000000000020e6  RSI: ffff891edbc377c8  RDI: 0000000000000000
    RBP: ffff891ee0003c18   R8: ffffffffc02f0b20   R9: 0000000000000250
    R10: 0000000000000258  R11: 000000000000b780  R12: ffff891ed9b43000
    R13: 00000000000000f0  R14: 0000000000000006  R15: ffff891edbc377c8
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #10 [ffff891ee0003c20] qla2x00_fcport_event_handler at ffffffffc02853d3 [qla2xxx]
 #11 [ffff891ee0003cf0] __dta_qla24xx_async_gnl_sp_done_333 at ffffffffc0285a1d [qla2xxx]
 #12 [ffff891ee0003de8] qla24xx_process_response_queue at ffffffffc02a2eb5 [qla2xxx]
 #13 [ffff891ee0003e88] qla24xx_msix_rsp_q at ffffffffc02a5403 [qla2xxx]
 #14 [ffff891ee0003ec0] __handle_irq_event_percpu at ffffffffbd0f4c59
 #15 [ffff891ee0003f10] handle_irq_event_percpu at ffffffffbd0f4e02
 #16 [ffff891ee0003f40] handle_irq_event at ffffffffbd0f4e90
 #17 [ffff891ee0003f68] handle_edge_irq at ffffffffbd0f8984
 #18 [ffff891ee0003f88] handle_irq at ffffffffbd0305d5
 #19 [ffff891ee0003fb8] do_IRQ at ffffffffbda02a18
 --- <IRQ stack> ---
 #20 [ffffffffbe403d30] ret_from_intr at ffffffffbda0094e
    [exception RIP: unknown or invalid address]
    RIP: 000000000000001f  RSP: 0000000000000000  RFLAGS: fff3b8c2091ebb3f
    RAX: ffffbba5a0000200  RBX: 0000be8cdfa8f9fa  RCX: 0000000000000018
    RDX: 0000000000000101  RSI: 000000000000015d  RDI: 0000000000000193
    RBP: 0000000000000083   R8: ffffffffbe403e38   R9: 0000000000000002
    R10: 0000000000000000  R11: ffffffffbe56b820  R12: ffff891ee001cf00
    R13: ffffffffbd11c0a4  R14: ffffffffbe403d60  R15: 0000000000000001
    ORIG_RAX: ffff891ee0022ac0  CS: 0000  SS: ffffffffffffffb9
 bt: WARNING: possibly bogus exception frame
 #21 [ffffffffbe403dd8] cpuidle_enter_state at ffffffffbd67c6fd
 #22 [ffffffffbe403e40] cpuidle_enter at ffffffffbd67c907
 #23 [ffffffffbe403e50] call_cpuidle at ffffffffbd0d98f3
 #24 [ffffffffbe403e60] do_idle at ffffffffbd0d9b42
 #25 [ffffffffbe403e98] cpu_startup_entry at ffffffffbd0d9da3
 #26 [ffffffffbe403ec0] rest_init at ffffffffbd81d4aa
 #27 [ffffffffbe403ed0] start_kernel at ffffffffbe67d2ca
 #28 [ffffffffbe403f28] x86_64_start_reservations at ffffffffbe67c675
 #29 [ffffffffbe403f38] x86_64_start_kernel at ffffffffbe67c6eb
 #30 [ffffffffbe403f50] secondary_startup_64 at ffffffffbd0000d5

Fixes: 040036b ("scsi: qla2xxx: Delay loop id allocation at login")
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 25, 2018

qmi_wwan: add support for the Dell Wireless 5821e module
[ Upstream commit e7e197e ]

This module exposes two USB configurations: a QMI+AT capable setup on
USB config #1 and a MBIM capable setup on USB config #2.

By default the kernel will choose the MBIM capable configuration as
long as the cdc_mbim driver is available. This patch adds support for
the QMI port in the secondary configuration.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 25, 2018

KEYS: DNS: fix parsing multiple options
commit c604cb7 upstream.

My recent fix for dns_resolver_preparse() printing very long strings was
incomplete, as shown by syzbot which still managed to hit the
WARN_ONCE() in set_precision() by adding a crafted "dns_resolver" key:

    precision 50001 too large
    WARNING: CPU: 7 PID: 864 at lib/vsprintf.c:2164 vsnprintf+0x48a/0x5a0

The bug this time isn't just a printing bug, but also a logical error
when multiple options ("#"-separated strings) are given in the key
payload.  Specifically, when separating an option string into name and
value, if there is no value then the name is incorrectly considered to
end at the end of the key payload, rather than the end of the current
option.  This bypasses validation of the option length, and also means
that specifying multiple options is broken -- which presumably has gone
unnoticed as there is currently only one valid option anyway.

A similar problem also applied to option values, as the kstrtoul() when
parsing the "dnserror" option will read past the end of the current
option and into the next option.

Fix these bugs by correctly computing the length of the option name and
by copying the option value, null-terminated, into a temporary buffer.

Reproducer for the WARN_ONCE() that syzbot hit:

    perl -e 'print "#A#", "\0" x 50000' | keyctl padd dns_resolver desc @s

Reproducer for "dnserror" option being parsed incorrectly (expected
behavior is to fail when seeing the unknown option "foo", actual
behavior was to read the dnserror value as "1#foo" and fail there):

    perl -e 'print "#dnserror=1#foo\0"' | keyctl padd dns_resolver desc @s

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 4a2d789 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Jul 30, 2018

MIPS: Use async IPIs for arch_trigger_cpumask_backtrace()
The current MIPS implementation of arch_trigger_cpumask_backtrace() is
broken because it attempts to use synchronous IPIs despite the fact that
it may be run with interrupts disabled.

This means that when arch_trigger_cpumask_backtrace() is invoked, for
example by the RCU CPU stall watchdog, we may:

  - Deadlock due to use of synchronous IPIs with interrupts disabled,
    causing the CPU that's attempting to generate the backtrace output
    to hang itself.

  - Not succeed in generating the desired output from remote CPUs.

  - Produce warnings about this from smp_call_function_many(), for
    example:

    [42760.526910] INFO: rcu_sched detected stalls on CPUs/tasks:
    [42760.535755]  0-...!: (1 GPs behind) idle=ade/140000000000000/0 softirq=526944/526945 fqs=0
    [42760.547874]  1-...!: (0 ticks this GP) idle=e4a/140000000000000/0 softirq=547885/547885 fqs=0
    [42760.559869]  (detected by 2, t=2162 jiffies, g=266689, c=266688, q=33)
    [42760.568927] ------------[ cut here ]------------
    [42760.576146] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:416 smp_call_function_many+0x88/0x20c
    [42760.587839] Modules linked in:
    [42760.593152] CPU: 2 PID: 1216 Comm: sh Not tainted 4.15.4-00373-gee058bb4d0c2 #2
    [42760.603767] Stack : 8e09bd20 8e09bd20 8e09bd20 fffffff0 00000007 00000006 00000000 8e09bca8
    [42760.616937]         95b2b379 95b2b379 807a0080 00000007 81944518 0000018a 00000032 00000000
    [42760.630095]         00000000 00000030 80000000 00000000 806eca74 00000009 8017e2b8 000001a0
    [42760.643169]         00000000 00000002 00000000 8e09baa4 00000008 808b8008 86d69080 8e09bca0
    [42760.656282]         8e09ad50 805e20aa 00000000 00000000 00000000 8017e2b8 00000009 801070ca
    [42760.669424]         ...
    [42760.673919] Call Trace:
    [42760.678672] [<27fde568>] show_stack+0x70/0xf0
    [42760.685417] [<84751641>] dump_stack+0xaa/0xd0
    [42760.692188] [<699d671c>] __warn+0x80/0x92
    [42760.698549] [<68915d41>] warn_slowpath_null+0x28/0x36
    [42760.705912] [<f7c76c1c>] smp_call_function_many+0x88/0x20c
    [42760.713696] [<6bbdfc2a>] arch_trigger_cpumask_backtrace+0x30/0x4a
    [42760.722216] [<f845bd33>] rcu_dump_cpu_stacks+0x6a/0x98
    [42760.729580] [<796e7629>] rcu_check_callbacks+0x672/0x6ac
    [42760.737476] [<059b3b43>] update_process_times+0x18/0x34
    [42760.744981] [<6eb94941>] tick_sched_handle.isra.5+0x26/0x38
    [42760.752793] [<478d3d70>] tick_sched_timer+0x1c/0x50
    [42760.759882] [<e56ea39f>] __hrtimer_run_queues+0xc6/0x226
    [42760.767418] [<e88bbcae>] hrtimer_interrupt+0x88/0x19a
    [42760.775031] [<6765a19e>] gic_compare_interrupt+0x2e/0x3a
    [42760.782761] [<0558bf5f>] handle_percpu_devid_irq+0x78/0x168
    [42760.790795] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
    [42760.798117] [<1b6d462c>] gic_handle_local_int+0x38/0x86
    [42760.805545] [<b2ada1c7>] gic_irq_dispatch+0xa/0x14
    [42760.812534] [<90c11ba2>] generic_handle_irq+0x1e/0x2c
    [42760.820086] [<c7521934>] do_IRQ+0x16/0x20
    [42760.826274] [<9aef3ce6>] plat_irq_dispatch+0x62/0x94
    [42760.833458] [<6a94b53c>] except_vec_vi_end+0x70/0x78
    [42760.840655] [<22284043>] smp_call_function_many+0x1ba/0x20c
    [42760.848501] [<54022b58>] smp_call_function+0x1e/0x2c
    [42760.855693] [<ab9fc705>] flush_tlb_mm+0x2a/0x98
    [42760.862730] [<0844cdd0>] tlb_flush_mmu+0x1c/0x44
    [42760.869628] [<cb259b74>] arch_tlb_finish_mmu+0x26/0x3e
    [42760.877021] [<1aeaaf74>] tlb_finish_mmu+0x18/0x66
    [42760.883907] [<b3fce717>] exit_mmap+0x76/0xea
    [42760.890428] [<c4c8a2f6>] mmput+0x80/0x11a
    [42760.896632] [<a41a08f4>] do_exit+0x1f4/0x80c
    [42760.903158] [<ee01cef6>] do_group_exit+0x20/0x7e
    [42760.909990] [<13fa8d54>] __wake_up_parent+0x0/0x1e
    [42760.917045] [<46cf89d0>] smp_call_function_many+0x1a2/0x20c
    [42760.924893] [<8c21a93b>] syscall_common+0x14/0x1c
    [42760.931765] ---[ end trace 02aa09da9dc52a60 ]---
    [42760.938342] ------------[ cut here ]------------
    [42760.945311] WARNING: CPU: 2 PID: 1216 at kernel/smp.c:291 smp_call_function_single+0xee/0xf8
    ...

This patch switches MIPS' arch_trigger_cpumask_backtrace() to use async
IPIs & smp_call_function_single_async() in order to resolve this
problem. We ensure use of the pre-allocated call_single_data_t
structures is serialized by maintaining a cpumask indicating that
they're busy, and refusing to attempt to send an IPI when a CPU's bit is
set in this mask. This should only happen if a CPU hasn't responded to a
previous backtrace IPI - ie. if it's hung - and we print a warning to
the console in this case.

I've marked this for stable branches as far back as v4.9, to which it
applies cleanly. Strictly speaking the faulty MIPS implementation can be
traced further back to commit 856839b ("MIPS: Add
arch_trigger_all_cpu_backtrace() function") in v3.19, but kernel
versions v3.19 through v4.8 will require further work to backport due to
the rework performed in commit 9a01c3e ("nmi_backtrace: add more
trigger_*_cpu_backtrace() methods").

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/19597/
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org # v4.9+
Fixes: 856839b ("MIPS: Add arch_trigger_all_cpu_backtrace() function")
Fixes: 9a01c3e ("nmi_backtrace: add more trigger_*_cpu_backtrace() methods")

popcornmix pushed a commit that referenced this issue Jul 30, 2018

scsi: qla2xxx: Fix NULL pointer dereference for fcport search
Crash dump shows following instructions

crash> bt
PID: 0      TASK: ffffffffbe412480  CPU: 0   COMMAND: "swapper/0"
 #0 [ffff891ee0003868] machine_kexec at ffffffffbd063ef1
 #1 [ffff891ee00038c8] __crash_kexec at ffffffffbd12b6f2
 #2 [ffff891ee0003998] crash_kexec at ffffffffbd12c84c
 #3 [ffff891ee00039b8] oops_end at ffffffffbd030f0a
 #4 [ffff891ee00039e0] no_context at ffffffffbd074643
 #5 [ffff891ee0003a40] __bad_area_nosemaphore at ffffffffbd07496e
 #6 [ffff891ee0003a90] bad_area_nosemaphore at ffffffffbd074a64
 #7 [ffff891ee0003aa0] __do_page_fault at ffffffffbd074b0a
 #8 [ffff891ee0003b18] do_page_fault at ffffffffbd074fc8
 #9 [ffff891ee0003b50] page_fault at ffffffffbda01925
    [exception RIP: qlt_schedule_sess_for_deletion+15]
    RIP: ffffffffc02e526f  RSP: ffff891ee0003c08  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: 0000000000000000  RCX: ffffffffc0307847
    RDX: 00000000000020e6  RSI: ffff891edbc377c8  RDI: 0000000000000000
    RBP: ffff891ee0003c18   R8: ffffffffc02f0b20   R9: 0000000000000250
    R10: 0000000000000258  R11: 000000000000b780  R12: ffff891ed9b43000
    R13: 00000000000000f0  R14: 0000000000000006  R15: ffff891edbc377c8
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #10 [ffff891ee0003c20] qla2x00_fcport_event_handler at ffffffffc02853d3 [qla2xxx]
 #11 [ffff891ee0003cf0] __dta_qla24xx_async_gnl_sp_done_333 at ffffffffc0285a1d [qla2xxx]
 #12 [ffff891ee0003de8] qla24xx_process_response_queue at ffffffffc02a2eb5 [qla2xxx]
 #13 [ffff891ee0003e88] qla24xx_msix_rsp_q at ffffffffc02a5403 [qla2xxx]
 #14 [ffff891ee0003ec0] __handle_irq_event_percpu at ffffffffbd0f4c59
 #15 [ffff891ee0003f10] handle_irq_event_percpu at ffffffffbd0f4e02
 #16 [ffff891ee0003f40] handle_irq_event at ffffffffbd0f4e90
 #17 [ffff891ee0003f68] handle_edge_irq at ffffffffbd0f8984
 #18 [ffff891ee0003f88] handle_irq at ffffffffbd0305d5
 #19 [ffff891ee0003fb8] do_IRQ at ffffffffbda02a18
 --- <IRQ stack> ---
 #20 [ffffffffbe403d30] ret_from_intr at ffffffffbda0094e
    [exception RIP: unknown or invalid address]
    RIP: 000000000000001f  RSP: 0000000000000000  RFLAGS: fff3b8c2091ebb3f
    RAX: ffffbba5a0000200  RBX: 0000be8cdfa8f9fa  RCX: 0000000000000018
    RDX: 0000000000000101  RSI: 000000000000015d  RDI: 0000000000000193
    RBP: 0000000000000083   R8: ffffffffbe403e38   R9: 0000000000000002
    R10: 0000000000000000  R11: ffffffffbe56b820  R12: ffff891ee001cf00
    R13: ffffffffbd11c0a4  R14: ffffffffbe403d60  R15: 0000000000000001
    ORIG_RAX: ffff891ee0022ac0  CS: 0000  SS: ffffffffffffffb9
 bt: WARNING: possibly bogus exception frame
 #21 [ffffffffbe403dd8] cpuidle_enter_state at ffffffffbd67c6fd
 #22 [ffffffffbe403e40] cpuidle_enter at ffffffffbd67c907
 #23 [ffffffffbe403e50] call_cpuidle at ffffffffbd0d98f3
 #24 [ffffffffbe403e60] do_idle at ffffffffbd0d9b42
 #25 [ffffffffbe403e98] cpu_startup_entry at ffffffffbd0d9da3
 #26 [ffffffffbe403ec0] rest_init at ffffffffbd81d4aa
 #27 [ffffffffbe403ed0] start_kernel at ffffffffbe67d2ca
 #28 [ffffffffbe403f28] x86_64_start_reservations at ffffffffbe67c675
 #29 [ffffffffbe403f38] x86_64_start_kernel at ffffffffbe67c6eb
 #30 [ffffffffbe403f50] secondary_startup_64 at ffffffffbd0000d5

Fixes: 040036b ("scsi: qla2xxx: Delay loop id allocation at login")
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

popcornmix pushed a commit that referenced this issue Jul 30, 2018

KEYS: DNS: fix parsing multiple options
My recent fix for dns_resolver_preparse() printing very long strings was
incomplete, as shown by syzbot which still managed to hit the
WARN_ONCE() in set_precision() by adding a crafted "dns_resolver" key:

    precision 50001 too large
    WARNING: CPU: 7 PID: 864 at lib/vsprintf.c:2164 vsnprintf+0x48a/0x5a0

The bug this time isn't just a printing bug, but also a logical error
when multiple options ("#"-separated strings) are given in the key
payload.  Specifically, when separating an option string into name and
value, if there is no value then the name is incorrectly considered to
end at the end of the key payload, rather than the end of the current
option.  This bypasses validation of the option length, and also means
that specifying multiple options is broken -- which presumably has gone
unnoticed as there is currently only one valid option anyway.

A similar problem also applied to option values, as the kstrtoul() when
parsing the "dnserror" option will read past the end of the current
option and into the next option.

Fix these bugs by correctly computing the length of the option name and
by copying the option value, null-terminated, into a temporary buffer.

Reproducer for the WARN_ONCE() that syzbot hit:

    perl -e 'print "#A#", "\0" x 50000' | keyctl padd dns_resolver desc @s

Reproducer for "dnserror" option being parsed incorrectly (expected
behavior is to fail when seeing the unknown option "foo", actual
behavior was to read the dnserror value as "1#foo" and fail there):

    perl -e 'print "#dnserror=1#foo\0"' | keyctl padd dns_resolver desc @s

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 4a2d789 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

popcornmix pushed a commit that referenced this issue Jul 30, 2018

Scott Bauer Christoph Hellwig
nvme: ensure forward progress during Admin passthru
If the controller supports effects and goes down during the passthru admin
command we will deadlock during namespace revalidation.

[  363.488275] INFO: task kworker/u16:5:231 blocked for more than 120 seconds.
[  363.488290]       Not tainted 4.17.0+ #2
[  363.488296] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  363.488303] kworker/u16:5   D    0   231      2 0x80000000
[  363.488331] Workqueue: nvme-reset-wq nvme_reset_work [nvme]
[  363.488338] Call Trace:
[  363.488385]  schedule+0x75/0x190
[  363.488396]  rwsem_down_read_failed+0x1c3/0x2f0
[  363.488481]  call_rwsem_down_read_failed+0x14/0x30
[  363.488504]  down_read+0x1d/0x80
[  363.488523]  nvme_stop_queues+0x1e/0xa0 [nvme_core]
[  363.488536]  nvme_dev_disable+0xae4/0x1620 [nvme]
[  363.488614]  nvme_reset_work+0xd1e/0x49d9 [nvme]
[  363.488911]  process_one_work+0x81a/0x1400
[  363.488934]  worker_thread+0x87/0xe80
[  363.488955]  kthread+0x2db/0x390
[  363.488977]  ret_from_fork+0x35/0x40

Fixes: 84fef62 ("nvme: check admin passthru command effects")
Signed-off-by: Scott Bauer <scott.bauer@intel.com>
Reviewed-by: Keith Busch <keith.busch@linux.intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

popcornmix pushed a commit that referenced this issue Jul 30, 2018

mm: disallow mappings that conflict for devm_memremap_pages()
When pmem namespaces created are smaller than section size, this can
cause an issue during removal and gpf was observed:

  general protection fault: 0000 1 SMP PTI
  CPU: 36 PID: 3941 Comm: ndctl Tainted: G W 4.14.28-1.el7uek.x86_64 #2
  task: ffff88acda150000 task.stack: ffffc900233a4000
  RIP: 0010:__put_page+0x56/0x79
  Call Trace:
    devm_memremap_pages_release+0x155/0x23a
    release_nodes+0x21e/0x260
    devres_release_all+0x3c/0x48
    device_release_driver_internal+0x15c/0x207
    device_release_driver+0x12/0x14
    unbind_store+0xba/0xd8
    drv_attr_store+0x27/0x31
    sysfs_kf_write+0x3f/0x46
    kernfs_fop_write+0x10f/0x18b
    __vfs_write+0x3a/0x16d
    vfs_write+0xb2/0x1a1
    SyS_write+0x55/0xb9
    do_syscall_64+0x79/0x1ae
    entry_SYSCALL_64_after_hwframe+0x3d/0x0

Add code to check whether we have a mapping already in the same section
and prevent additional mappings from being created if that is the case.

Link: http://lkml.kernel.org/r/152909478401.50143.312364396244072931.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

peyo-hd pushed a commit to peyo-hd/kernel_rpi that referenced this issue Aug 1, 2018

f2fs: fix to avoid race in between atomic write and background GC
Sqlite user			Background GC
				- move_data_block
				  : move page #1
				 - f2fs_is_atomic_file
- f2fs_ioc_start_atomic_write
- f2fs_ioc_commit_atomic_write
 - commit_inmem_pages
   : commit page #1 & set node #2 dirty
				 - f2fs_submit_page_write
				  - f2fs_update_data_blkaddr
				   - set_page_dirty
				     : set node #2 dirty
 - f2fs_do_sync_file
  - fsync_node_pages
   : commit node #1 & node #2, then sudden power-cut

In a race case, we may check FI_ATOMIC_FILE flag before starting atomic
write flow, then we will commit meta data before data with reversed
order, after a sudden pow-cut, database transaction will be inconsistent.

So we'd better to exclude gc/atomic_write to each other by using lock
instead of flag checking.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

peyo-hd pushed a commit to peyo-hd/kernel_rpi that referenced this issue Aug 1, 2018

Jaegeuk Kim
f2fs: avoid bug_on on corrupted inode
syzbot has tested the proposed patch but the reproducer still triggered crash:
kernel BUG at fs/f2fs/inode.c:LINE!

F2FS-fs (loop1): invalid crc value
F2FS-fs (loop5): Magic Mismatch, valid(0xf2f52010) - read(0x0)
F2FS-fs (loop5): Can't find valid F2FS filesystem in 1th superblock
F2FS-fs (loop5): invalid crc value
------------[ cut here ]------------
kernel BUG at fs/f2fs/inode.c:238!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4886 Comm: syz-executor1 Not tainted 4.17.0-rc1+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:do_read_inode fs/f2fs/inode.c:238 [inline]
RIP: 0010:f2fs_iget+0x3307/0x3ca0 fs/f2fs/inode.c:313
RSP: 0018:ffff8801c44a70e8 EFLAGS: 00010293
RAX: ffff8801ce208040 RBX: ffff8801b3621080 RCX: ffffffff82eace18
F2FS-fs (loop2): Magic Mismatch, valid(0xf2f52010) - read(0x0)
RDX: 0000000000000000 RSI: ffffffff82eaf047 RDI: 0000000000000007
RBP: ffff8801c44a7410 R08: ffff8801ce208040 R09: ffffed0039ee4176
R10: ffffed0039ee4176 R11: ffff8801cf720bb7 R12: ffff8801c0efa000
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f753aa9d700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
------------[ cut here ]------------
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kernel BUG at fs/f2fs/inode.c:238!
CR2: 0000000001b03018 CR3: 00000001c8b74000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 f2fs_fill_super+0x4377/0x7bf0 fs/f2fs/super.c:2842
 mount_bdev+0x30c/0x3e0 fs/super.c:1165
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:3020
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 __do_sys_mount fs/namespace.c:3077 [inline]
 __se_sys_mount fs/namespace.c:3074 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457daa
RSP: 002b:00007f753aa9cba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000000 RCX: 0000000000457daa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f753aa9cbf0
RBP: 0000000000000064 R08: 0000000020016a00 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000064 R14: 00000000006fcb80 R15: 0000000000000000
RIP: do_read_inode fs/f2fs/inode.c:238 [inline] RSP: ffff8801c44a70e8
RIP: f2fs_iget+0x3307/0x3ca0 fs/f2fs/inode.c:313 RSP: ffff8801c44a70e8
invalid opcode: 0000 [#2] SMP KASAN
---[ end trace 1cbcbec2156680bc ]---

Reported-and-tested-by: syzbot+41a1b341571f0952badb@syzkaller.appspotmail.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

list_bl: Make list head locking RT safe
As per changes in include/linux/jbd_common.h for avoiding the
bit_spin_locks on RT ("fs: jbd/jbd2: Make state lock and journal
head lock rt safe") we do the same thing here.

We use the non atomic __set_bit and __clear_bit inside the scope of
the lock to preserve the ability of the existing LIST_DEBUG code to
use the zero'th bit in the sanity checks.

As a bit spinlock, we had no lockdep visibility into the usage
of the list head locking.  Now, if we were to implement it as a
standard non-raw spinlock, we would see:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:658
in_atomic(): 1, irqs_disabled(): 0, pid: 122, name: udevd
5 locks held by udevd/122:
 #0:  (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [<ffffffff811967e8>] lock_rename+0xe8/0xf0
 #1:  (rename_lock){+.+...}, at: [<ffffffff811a277c>] d_move+0x2c/0x60
 #2:  (&dentry->d_lock){+.+...}, at: [<ffffffff811a0763>] dentry_lock_for_move+0xf3/0x130
 #3:  (&dentry->d_lock/2){+.+...}, at: [<ffffffff811a0734>] dentry_lock_for_move+0xc4/0x130
 #4:  (&dentry->d_lock/3){+.+...}, at: [<ffffffff811a0747>] dentry_lock_for_move+0xd7/0x130
Pid: 122, comm: udevd Not tainted 3.4.47-rt62 #7
Call Trace:
 [<ffffffff810b9624>] __might_sleep+0x134/0x1f0
 [<ffffffff817a24d4>] rt_spin_lock+0x24/0x60
 [<ffffffff811a0c4c>] __d_shrink+0x5c/0xa0
 [<ffffffff811a1b2d>] __d_drop+0x1d/0x40
 [<ffffffff811a24be>] __d_move+0x8e/0x320
 [<ffffffff811a278e>] d_move+0x3e/0x60
 [<ffffffff81199598>] vfs_rename+0x198/0x4c0
 [<ffffffff8119b093>] sys_renameat+0x213/0x240
 [<ffffffff817a2de5>] ? _raw_spin_unlock+0x35/0x60
 [<ffffffff8107781c>] ? do_page_fault+0x1ec/0x4b0
 [<ffffffff817a32ca>] ? retint_swapgs+0xe/0x13
 [<ffffffff813eb0e6>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8119b0db>] sys_rename+0x1b/0x20
 [<ffffffff817a3b96>] system_call_fastpath+0x1a/0x1f

Since we are only taking the lock during short lived list operations,
lets assume for now that it being raw won't be a significant latency
concern.


Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

mm/memcontrol: Don't call schedule_work_on in preemption disabled con…
…text

The following trace is triggered when running ltp oom test cases:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:659
in_atomic(): 1, irqs_disabled(): 0, pid: 17188, name: oom03
Preemption disabled at:[<ffffffff8112ba70>] mem_cgroup_reclaim+0x90/0xe0

CPU: 2 PID: 17188 Comm: oom03 Not tainted 3.10.10-rt3 #2
Hardware name: Intel Corporation Calpella platform/MATXM-CORE-411-B, BIOS 4.6.3 08/18/2010
ffff88007684d730 ffff880070df9b58 ffffffff8169918d ffff880070df9b70
ffffffff8106db31 ffff88007688b4a0 ffff880070df9b88 ffffffff8169d9c0
ffff88007688b4a0 ffff880070df9bc8 ffffffff81059da1 0000000170df9bb0
Call Trace:
[<ffffffff8169918d>] dump_stack+0x19/0x1b
[<ffffffff8106db31>] __might_sleep+0xf1/0x170
[<ffffffff8169d9c0>] rt_spin_lock+0x20/0x50
[<ffffffff81059da1>] queue_work_on+0x61/0x100
[<ffffffff8112b361>] drain_all_stock+0xe1/0x1c0
[<ffffffff8112ba70>] mem_cgroup_reclaim+0x90/0xe0
[<ffffffff8112beda>] __mem_cgroup_try_charge+0x41a/0xc40
[<ffffffff810f1c91>] ? release_pages+0x1b1/0x1f0
[<ffffffff8106f200>] ? sched_exec+0x40/0xb0
[<ffffffff8112cc87>] mem_cgroup_charge_common+0x37/0x70
[<ffffffff8112e2c6>] mem_cgroup_newpage_charge+0x26/0x30
[<ffffffff8110af68>] handle_pte_fault+0x618/0x840
[<ffffffff8103ecf6>] ? unpin_current_cpu+0x16/0x70
[<ffffffff81070f94>] ? migrate_enable+0xd4/0x200
[<ffffffff8110cde5>] handle_mm_fault+0x145/0x1e0
[<ffffffff810301e1>] __do_page_fault+0x1a1/0x4c0
[<ffffffff8169c9eb>] ? preempt_schedule_irq+0x4b/0x70
[<ffffffff8169e3b7>] ? retint_kernel+0x37/0x40
[<ffffffff8103053e>] do_page_fault+0xe/0x10
[<ffffffff8169e4c2>] page_fault+0x22/0x30

So, to prevent schedule_work_on from being called in preempt disabled context,
replace the pair of get/put_cpu() to get/put_cpu_light().


Signed-off-by: Yang Shi <yang.shi@windriver.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

hrtimer: Move schedule_work call to helper thread
When run ltp leapsec_timer test, the following call trace is caught:

BUG: sleeping function called from invalid context at kernel/rtmutex.c:659
in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1
Preemption disabled at:[<ffffffff810857f3>] cpu_startup_entry+0x133/0x310

CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.10.10-rt3 #2
Hardware name: Intel Corporation Calpella platform/MATXM-CORE-411-B, BIOS 4.6.3 08/18/2010
ffffffff81c2f800 ffff880076843e40 ffffffff8169918d ffff880076843e58
ffffffff8106db31 ffff88007684b4a0 ffff880076843e70 ffffffff8169d9c0
ffff88007684b4a0 ffff880076843eb0 ffffffff81059da1 0000001876851200
Call Trace:
<IRQ>  [<ffffffff8169918d>] dump_stack+0x19/0x1b
[<ffffffff8106db31>] __might_sleep+0xf1/0x170
[<ffffffff8169d9c0>] rt_spin_lock+0x20/0x50
[<ffffffff81059da1>] queue_work_on+0x61/0x100
[<ffffffff81065aa1>] clock_was_set_delayed+0x21/0x30
[<ffffffff810883be>] do_timer+0x40e/0x660
[<ffffffff8108f487>] tick_do_update_jiffies64+0xf7/0x140
[<ffffffff8108fe42>] tick_check_idle+0x92/0xc0
[<ffffffff81044327>] irq_enter+0x57/0x70
[<ffffffff816a040e>] smp_apic_timer_interrupt+0x3e/0x9b
[<ffffffff8169f80a>] apic_timer_interrupt+0x6a/0x70
<EOI>  [<ffffffff8155ea1c>] ? cpuidle_enter_state+0x4c/0xc0
[<ffffffff8155eb68>] cpuidle_idle_call+0xd8/0x2d0
[<ffffffff8100b59e>] arch_cpu_idle+0xe/0x30
[<ffffffff8108585e>] cpu_startup_entry+0x19e/0x310
[<ffffffff8168efa2>] start_secondary+0x1ad/0x1b0

The clock_was_set_delayed is called in hard IRQ handler (timer interrupt), which
calls schedule_work.

Under PREEMPT_RT_FULL, schedule_work calls spinlocks which could sleep, so it's
not safe to call schedule_work in interrupt context.

Reference upstream commit b68d61c705ef02384c0538b8d9374545097899ca
(rt,ntp: Move call to schedule_delayed_work() to helper thread)
from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git, which
makes a similar change.

Signed-off-by: Yang Shi <yang.shi@windriver.com>
[bigeasy: use swork_queue() instead a helper thread]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

block: blk-mq: move blk_queue_usage_counter_release() into process co…
…ntext

| BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:914
| in_atomic(): 1, irqs_disabled(): 0, pid: 255, name: kworker/u257:6
| 5 locks held by kworker/u257:6/255:
|  #0:  ("events_unbound"){.+.+.+}, at: [<ffffffff8108edf1>] process_one_work+0x171/0x5e0
|  #1:  ((&entry->work)){+.+.+.}, at: [<ffffffff8108edf1>] process_one_work+0x171/0x5e0
|  #2:  (&shost->scan_mutex){+.+.+.}, at: [<ffffffffa000faa3>] __scsi_add_device+0xa3/0x130 [scsi_mod]
|  #3:  (&set->tag_list_lock){+.+...}, at: [<ffffffff812f09fa>] blk_mq_init_queue+0x96a/0xa50
|  #4:  (rcu_read_lock_sched){......}, at: [<ffffffff8132887d>] percpu_ref_kill_and_confirm+0x1d/0x120
| Preemption disabled at:[<ffffffff812eff76>] blk_mq_freeze_queue_start+0x56/0x70
|
| CPU: 2 PID: 255 Comm: kworker/u257:6 Not tainted 3.18.7-rt0+ #1
| Workqueue: events_unbound async_run_entry_fn
|  0000000000000003 ffff8800bc29f998 ffffffff815b3a12 0000000000000000
|  0000000000000000 ffff8800bc29f9b8 ffffffff8109aa16 ffff8800bc29fa28
|  ffff8800bc5d1bc8 ffff8800bc29f9e8 ffffffff815b8dd4 ffff880000000000
| Call Trace:
|  [<ffffffff815b3a12>] dump_stack+0x4f/0x7c
|  [<ffffffff8109aa16>] __might_sleep+0x116/0x190
|  [<ffffffff815b8dd4>] rt_spin_lock+0x24/0x60
|  [<ffffffff810b6089>] __wake_up+0x29/0x60
|  [<ffffffff812ee06e>] blk_mq_usage_counter_release+0x1e/0x20
|  [<ffffffff81328966>] percpu_ref_kill_and_confirm+0x106/0x120
|  [<ffffffff812eff76>] blk_mq_freeze_queue_start+0x56/0x70
|  [<ffffffff812f0000>] blk_mq_update_tag_set_depth+0x40/0xd0
|  [<ffffffff812f0a1c>] blk_mq_init_queue+0x98c/0xa50
|  [<ffffffffa000dcf0>] scsi_mq_alloc_queue+0x20/0x60 [scsi_mod]
|  [<ffffffffa000ea35>] scsi_alloc_sdev+0x2f5/0x370 [scsi_mod]
|  [<ffffffffa000f494>] scsi_probe_and_add_lun+0x9e4/0xdd0 [scsi_mod]
|  [<ffffffffa000fb26>] __scsi_add_device+0x126/0x130 [scsi_mod]
|  [<ffffffffa013033f>] ata_scsi_scan_host+0xaf/0x200 [libata]
|  [<ffffffffa012b5b6>] async_port_probe+0x46/0x60 [libata]
|  [<ffffffff810978fb>] async_run_entry_fn+0x3b/0xf0
|  [<ffffffff8108ee81>] process_one_work+0x201/0x5e0

percpu_ref_kill_and_confirm() invokes blk_mq_usage_counter_release() in
a rcu-sched region. swait based wake queue can't be used due to
wake_up_all() usage and disabled interrupts in !RT configs (as reported
by Corey Minyard).
The wq_has_sleeper() check has been suggested by Peter Zijlstra.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

sas-ata/isci: dont't disable interrupts in qc_issue handler
On 3.14-rt we see the following trace on Canoe Pass for
SCSI_ISCI "Intel(R) C600 Series Chipset SAS Controller"
when the sas qc_issue handler is run:

 BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:905
 in_atomic(): 0, irqs_disabled(): 1, pid: 432, name: udevd
 CPU: 11 PID: 432 Comm: udevd Not tainted 3.14.28-rt22 #2
 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS SE5C600.86B.02.01.0002.082220131453 08/22/2013
 ffff880fab500000 ffff880fa9f239c0 ffffffff81a2d273 0000000000000000
 ffff880fa9f239d8 ffffffff8107f023 ffff880faac23dc0 ffff880fa9f239f0
 ffffffff81a33cc0 ffff880faaeb1400 ffff880fa9f23a40 ffffffff815de891
 Call Trace:
 [<ffffffff81a2d273>] dump_stack+0x4e/0x7a
 [<ffffffff8107f023>] __might_sleep+0xe3/0x160
 [<ffffffff81a33cc0>] rt_spin_lock+0x20/0x50
 [<ffffffff815de891>] isci_task_execute_task+0x171/0x2f0  <-----
 [<ffffffff815cfecb>] sas_ata_qc_issue+0x25b/0x2a0
 [<ffffffff81606363>] ata_qc_issue+0x1f3/0x370
 [<ffffffff8160c600>] ? ata_scsi_invalid_field+0x40/0x40
 [<ffffffff8160c8f5>] ata_scsi_translate+0xa5/0x1b0
 [<ffffffff8160efc6>] ata_sas_queuecmd+0x86/0x280
 [<ffffffff815ce446>] sas_queuecommand+0x196/0x230
 [<ffffffff81081fad>] ? get_parent_ip+0xd/0x50
 [<ffffffff815b05a4>] scsi_dispatch_cmd+0xb4/0x210
 [<ffffffff815b7744>] scsi_request_fn+0x314/0x530

and gdb shows:

(gdb) list * isci_task_execute_task+0x171
0xffffffff815ddfb1 is in isci_task_execute_task (drivers/scsi/isci/task.c:138).
133             dev_dbg(&ihost->pdev->dev, "%s: num=%d\n", __func__, num);
134
135             for_each_sas_task(num, task) {
136                     enum sci_status status = SCI_FAILURE;
137
138                     spin_lock_irqsave(&ihost->scic_lock, flags);    <-----
139                     idev = isci_lookup_device(task->dev);
140                     io_ready = isci_device_io_ready(idev, task);
141                     tag = isci_alloc_tag(ihost);
142                     spin_unlock_irqrestore(&ihost->scic_lock, flags);
(gdb)

In addition to the scic_lock, the function also contains locking of
the task_state_lock -- which is clearly not a candidate for raw lock
conversion.  As can be seen by the comment nearby, we really should
be running the qc_issue code with interrupts enabled anyway.


Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

TiejunChina pushed a commit that referenced this issue Aug 2, 2018

char/random: don't print that the init is done
On RT we run into circular locking with pendingb_lock (workqueue),
port_lock_key (uart) and the primary_crng (random):

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 -------------------------------------------------------
 irq/4-serial/512 is trying to acquire lock:
  ((pendingb_lock).lock){+.+...}, at: [<ffffffff8108d48d>] queue_work_on+0x5d/0x190

 but task is already holding lock:
  (&port_lock_key){+.+...}, at: [<ffffffff815b4bb6>] serial8250_handle_irq.part.27+0x16/0xb0

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&port_lock_key){+.+...}:
        lock_acquire+0xac/0x240
        rt_spin_lock+0x46/0x50
        serial8250_console_write+0x211/0x220
        univ8250_console_write+0x1c/0x20
        console_unlock+0x563/0x5c0
        vprintk_emit+0x277/0x320
        vprintk_default+0x1a/0x20
        vprintk_func+0x20/0x80
        printk+0x3e/0x46
        crng_fast_load+0xde/0xe0
        add_interrupt_randomness+0x16c/0x1a0
        irq_thread+0x15c/0x1e0
        kthread+0x112/0x150
        ret_from_fork+0x31/0x40

 -> #2 (primary_crng.lock){+.+...}:
        lock_acquire+0xac/0x240
        rt_spin_lock+0x46/0x50
        _extract_crng+0x39/0xa0
        extract_crng+0x3a/0x40
        get_random_u32+0x120/0x190
        new_slab+0x1d6/0x7c0
        ___slab_alloc+0x30b/0x6f0
        __slab_alloc.isra.78+0x6c/0xc0
        __kmalloc+0x254/0x3a0
        pcpu_mem_zalloc+0x3a/0x70
        percpu_init_late+0x4f/0x8a
        start_kernel+0x1ec/0x3b8
        x86_64_start_reservations+0x2a/0x2c
        x86_64_start_kernel+0x13d/0x14c
        verify_cpu+0x0/0xfc

 -> #1 ((batched_entropy_u32_lock).lock){+.+...}:
        lock_acquire+0xac/0x240
        rt_spin_lock__no_mg+0x41/0x50
        get_random_u32+0x64/0x190
        new_slab+0x1d6/0x7c0
        ___slab_alloc+0x30b/0x6f0
        __slab_alloc.isra.78+0x6c/0xc0
        kmem_cache_alloc+0x26a/0x370
        __debug_object_init+0x325/0x460
        debug_object_activate+0x11c/0x1f0
        __queue_work+0x2c/0x770
        queue_work_on+0x12a/0x190
        serio_queue_event+0xd3/0x140
        __serio_register_port+0x17e/0x1a0
        i8042_probe+0x623/0x687
        platform_drv_probe+0x36/0x90
        driver_probe_device+0x1f8/0x2e0
        __driver_attach+0x96/0xa0
        bus_for_each_dev+0x5d/0x90
        driver_attach+0x19/0x20
        bus_add_driver+0x125/0x220
        driver_register+0x5b/0xd0
        __platform_driver_probe+0x5b/0x120
        __platform_create_bundle+0xaa/0xd0
        i8042_init+0x3f1/0x430
        do_one_initcall+0x3e/0x180
        kernel_init_freeable+0x212/0x295
        kernel_init+0x9/0x100
        ret_from_fork+0x31/0x40

 -> #0 ((pendingb_lock).lock){+.+...}:
        __lock_acquire+0x11b4/0x1320
        lock_acquire+0xac/0x240
        rt_spin_lock+0x46/0x50
        queue_work_on+0x5d/0x190
        tty_flip_buffer_push+0x26/0x30
        serial8250_rx_chars+0x120/0x1f0
        serial8250_handle_irq.part.27+0x58/0xb0
        serial8250_default_handle_irq+0x4b/0x60
        serial8250_interrupt+0x5f/0xd0
        irq_forced_thread_fn+0x1e/0x70
        irq_thread+0x137/0x1e0
        kthread+0x112/0x150
        ret_from_fork+0x31/0x40

 other info that might help us debug this:

 Chain exists of:
   (pendingb_lock).lock --> primary_crng.lock --> &port_lock_key

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&port_lock_key);
                                lock(primary_crng.lock);
                                lock(&port_lock_key);
   lock((pendingb_lock).lock);

  *** DEADLOCK ***

 2 locks held by irq/4-serial/512:
  #0:  (&i->lock){+.+...}, at: [<ffffffff815b0400>] serial8250_interrupt+0x30/0xd0
  #1:  (&port_lock_key){+.+...}, at: [<ffffffff815b4bb6>] serial8250_handle_irq.part.27+0x16/0xb0

 stack backtrace:
 CPU: 4 PID: 512 Comm: irq/4-serial Not tainted 4.11.3-rt0+ #101
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1 04/01/2014
 Call Trace:
  dump_stack+0x86/0xc1
  print_circular_bug+0x1be/0x210
  __lock_acquire+0x11b4/0x1320
  lock_acquire+0xac/0x240
  rt_spin_lock+0x46/0x50
  queue_work_on+0x5d/0x190
  tty_flip_buffer_push+0x26/0x30
  serial8250_rx_chars+0x120/0x1f0
  serial8250_handle_irq.part.27+0x58/0xb0
  serial8250_default_handle_irq+0x4b/0x60
  serial8250_interrupt+0x5f/0xd0
  irq_forced_thread_fn+0x1e/0x70
  irq_thread+0x137/0x1e0
  kthread+0x112/0x150
  ret_from_fork+0x31/0x40

It should work if we delay that printk after dropping the lock but we
also could skip it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

mm: disallow mappings that conflict for devm_memremap_pages()
commit 15d36fe upstream.

When pmem namespaces created are smaller than section size, this can
cause an issue during removal and gpf was observed:

  general protection fault: 0000 1 SMP PTI
  CPU: 36 PID: 3941 Comm: ndctl Tainted: G W 4.14.28-1.el7uek.x86_64 #2
  task: ffff88acda150000 task.stack: ffffc900233a4000
  RIP: 0010:__put_page+0x56/0x79
  Call Trace:
    devm_memremap_pages_release+0x155/0x23a
    release_nodes+0x21e/0x260
    devres_release_all+0x3c/0x48
    device_release_driver_internal+0x15c/0x207
    device_release_driver+0x12/0x14
    unbind_store+0xba/0xd8
    drv_attr_store+0x27/0x31
    sysfs_kf_write+0x3f/0x46
    kernfs_fop_write+0x10f/0x18b
    __vfs_write+0x3a/0x16d
    vfs_write+0xb2/0x1a1
    SyS_write+0x55/0xb9
    do_syscall_64+0x79/0x1ae
    entry_SYSCALL_64_after_hwframe+0x3d/0x0

Add code to check whether we have a mapping already in the same section
and prevent additional mappings from being created if that is the case.

Link: http://lkml.kernel.org/r/152909478401.50143.312364396244072931.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

kernel/hung_task.c: show all hung tasks before panic
[ Upstream commit 401c636 ]

When we get a hung task it can often be valuable to see _all_ the hung
tasks on the system before calling panic().

Quoting from https://syzkaller.appspot.com/text?tag=CrashReport&id=5316056503549952
----------------------------------------
INFO: task syz-executor0:6540 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D23560  6540   4521 0x80000004
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x8fb/0x1ef0 kernel/sched/core.c:3490
 schedule+0xf5/0x430 kernel/sched/core.c:3549
 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3607
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0xb7f/0x1810 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601
 ioctl_by_bdev+0xa5/0x110 fs/block_dev.c:2060
 isofs_get_last_session fs/isofs/inode.c:567 [inline]
 isofs_fill_super+0x2ba9/0x3bc0 fs/isofs/inode.c:660
 mount_bdev+0x2b7/0x370 fs/super.c:1119
 isofs_mount+0x34/0x40 fs/isofs/inode.c:1560
 mount_fs+0x66/0x2d0 fs/super.c:1222
 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:2514 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0xea4/0x2b90 fs/namespace.c:2847
 ksys_mount+0xab/0x120 fs/namespace.c:3063
 SYSC_mount fs/namespace.c:3077 [inline]
 SyS_mount+0x39/0x50 fs/namespace.c:3074
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
(...snipped...)
Showing all locks held in the system:
(...snipped...)
2 locks held by syz-executor0/6540:
 #0: 00000000566d4c39 (&type->s_umount_key#49/1){+.+.}, at: alloc_super fs/super.c:211 [inline]
 #0: 00000000566d4c39 (&type->s_umount_key#49/1){+.+.}, at: sget_userns+0x3b2/0xe60 fs/super.c:502 /* down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); */
 #1: 0000000043ca8836 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 /* mutex_lock_nested(&lo->lo_ctl_mutex, 1); */
(...snipped...)
3 locks held by syz-executor7/6541:
 #0: 0000000043ca8836 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 /* mutex_lock_nested(&lo->lo_ctl_mutex, 1); */
 #1: 000000007bf3d3f9 (&bdev->bd_mutex){+.+.}, at: blkdev_reread_part+0x1e/0x40 block/ioctl.c:192
 #2: 00000000566d4c39 (&type->s_umount_key#50){.+.+}, at: __get_super.part.10+0x1d3/0x280 fs/super.c:663 /* down_read(&sb->s_umount); */
----------------------------------------

When reporting an AB-BA deadlock like shown above, it would be nice if
trace of PID=6541 is printed as well as trace of PID=6540 before calling
panic().

Showing hung tasks up to /proc/sys/kernel/hung_task_warnings could delay
calling panic() but normally there should not be so many hung tasks.

Link: http://lkml.kernel.org/r/201804050705.BHE57833.HVFOFtSOMQJFOL@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

scsi: qedf: Set the UNLOADING flag when removing a vport
[ Upstream commit 4f4616c ]

Similar to what we do when we remove a PCI function, set the
QEDF_UNLOADING flag to prevent any requests from being queued while a
vport is being deleted.  This prevents any requests from getting stuck
in limbo when the vport is unloaded or deleted.

Fixes the crash:

PID: 106676  TASK: ffff9a436aa90000  CPU: 12  COMMAND: "multipathd"
 #0 [ffff9a43567d3550] machine_kexec+522 at ffffffffaca60b2a
 #1 [ffff9a43567d35b0] __crash_kexec+114 at ffffffffacb13512
 #2 [ffff9a43567d3680] crash_kexec+48 at ffffffffacb13600
 #3 [ffff9a43567d3698] oops_end+168 at ffffffffad117768
 #4 [ffff9a43567d36c0] no_context+645 at ffffffffad106f52
 #5 [ffff9a43567d3710] __bad_area_nosemaphore+116 at ffffffffad106fe9
 #6 [ffff9a43567d3760] bad_area+70 at ffffffffad107379
 #7 [ffff9a43567d3788] __do_page_fault+1247 at ffffffffad11a8cf
 #8 [ffff9a43567d37f0] do_page_fault+53 at ffffffffad11a915
 #9 [ffff9a43567d3820] page_fault+40 at ffffffffad116768
    [exception RIP: qedf_init_task+61]
    RIP: ffffffffc0e13c2d  RSP: ffff9a43567d38d0  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: ffffbe920472c738  RCX: ffff9a434fa0e3e8
    RDX: ffff9a434f695280  RSI: ffffbe920472c738  RDI: ffff9a43aa359c80
    RBP: ffff9a43567d3950   R8: 0000000000000c15   R9: ffff9a3fb09b9880
    R10: ffff9a434fa0e3e8  R11: ffff9a43567d35ce  R12: 0000000000000000
    R13: ffff9a434f695280  R14: ffff9a43aa359c80  R15: ffff9a3fb9e005c0
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Signed-off-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

bonding: avoid lockdep confusion in bond_get_stats()
[ Upstream commit 7e2556e ]

syzbot found that the following sequence produces a LOCKDEP splat [1]

ip link add bond10 type bond
ip link add bond11 type bond
ip link set bond11 master bond10

To fix this, we can use the already provided nest_level.

This patch also provides correct nesting for dev->addr_list_lock

[1]
WARNING: possible recursive locking detected
4.18.0-rc6+ #167 Not tainted
--------------------------------------------
syz-executor751/4439 is trying to acquire lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

but task is already holding lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&bond->stats_lock)->rlock);
  lock(&(&bond->stats_lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor751/4439:
 #0: (____ptrval____) (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 #2: (____ptrval____) (rcu_read_lock){....}, at: bond_get_stats+0x0/0x560 include/linux/compiler.h:215

stack backtrace:
CPU: 0 PID: 4439 Comm: syz-executor751 Not tainted 4.18.0-rc6+ #167
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_deadlock_bug kernel/locking/lockdep.c:1765 [inline]
 check_deadlock kernel/locking/lockdep.c:1809 [inline]
 validate_chain kernel/locking/lockdep.c:2405 [inline]
 __lock_acquire.cold.64+0x1fb/0x486 kernel/locking/lockdep.c:3435
 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
 spin_lock include/linux/spinlock.h:310 [inline]
 bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 bond_get_stats+0x232/0x560 drivers/net/bonding/bond_main.c:3432
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 rtnl_fill_stats+0x4d/0xac0 net/core/rtnetlink.c:1169
 rtnl_fill_ifinfo+0x1aa6/0x3fb0 net/core/rtnetlink.c:1611
 rtmsg_ifinfo_build_skb+0xc8/0x190 net/core/rtnetlink.c:3268
 rtmsg_ifinfo_event.part.30+0x45/0xe0 net/core/rtnetlink.c:3300
 rtmsg_ifinfo_event net/core/rtnetlink.c:3297 [inline]
 rtnetlink_event+0x144/0x170 net/core/rtnetlink.c:4716
 notifier_call_chain+0x180/0x390 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1735
 call_netdevice_notifiers net/core/dev.c:1753 [inline]
 netdev_features_change net/core/dev.c:1321 [inline]
 netdev_change_features+0xb3/0x110 net/core/dev.c:7759
 bond_compute_features.isra.47+0x585/0xa50 drivers/net/bonding/bond_main.c:1120
 bond_enslave+0x1b25/0x5da0 drivers/net/bonding/bond_main.c:1755
 bond_do_ioctl+0x7cb/0xae0 drivers/net/bonding/bond_main.c:3528
 dev_ifsioc+0x43c/0xb30 net/core/dev_ioctl.c:327
 dev_ioctl+0x1b5/0xcc0 net/core/dev_ioctl.c:493
 sock_do_ioctl+0x1d3/0x3e0 net/socket.c:992
 sock_ioctl+0x30d/0x680 net/socket.c:1093
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440859
Code: e8 2c af 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc51a92878 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440859
RDX: 0000000020000040 RSI: 0000000000008990 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000022d5880 R11: 0000000000000213 R12: 0000000000007390
R13: 0000000000401db0 R14: 0000000000000000 R15: 0000000000000000

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

virtio_balloon: fix another race between migration and ballooning
commit 89da619 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: stable@vger.kernel.org
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Huang Chong <huang.chong@zte.com.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

ipc/shm.c add ->pagesize function to shm_vm_ops
commit eec3636 upstream.

Commit 05ea886 ("mm, hugetlbfs: introduce ->pagesize() to
vm_operations_struct") adds a new ->pagesize() function to
hugetlb_vm_ops, intended to cover all hugetlbfs backed files.

With System V shared memory model, if "huge page" is specified, the
"shared memory" is backed by hugetlbfs files, but the mappings initiated
via shmget/shmat have their original vm_ops overwritten with shm_vm_ops,
so we need to add a ->pagesize function to shm_vm_ops.  Otherwise,
vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs backed vma,
result in below BUG:

  fs/hugetlbfs/inode.c
        443             if (unlikely(page_mapped(page))) {
        444                     BUG_ON(truncate_op);

resulting in

  hugetlbfs: oracle (4592): Using mlock ulimits for SHM_HUGETLB is deprecated
  ------------[ cut here ]------------
  kernel BUG at fs/hugetlbfs/inode.c:444!
  Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 ...
  CPU: 35 PID: 5583 Comm: oracle_5583_sbt Not tainted 4.14.35-1829.el7uek.x86_64 #2
  RIP: 0010:remove_inode_hugepages+0x3db/0x3e2
  ....
  Call Trace:
    hugetlbfs_evict_inode+0x1e/0x3e
    evict+0xdb/0x1af
    iput+0x1a2/0x1f7
    dentry_unlink_inode+0xc6/0xf0
    __dentry_kill+0xd8/0x18d
    dput+0x1b5/0x1ed
    __fput+0x18b/0x216
    ____fput+0xe/0x10
    task_work_run+0x90/0xa7
    exit_to_usermode_loop+0xdd/0x116
    do_syscall_64+0x187/0x1ae
    entry_SYSCALL_64_after_hwframe+0x150/0x0

[jane.chu@oracle.com: relocate comment]
  Link: http://lkml.kernel.org/r/20180731044831.26036-1-jane.chu@oracle.com
Link: http://lkml.kernel.org/r/20180727211727.5020-1-jane.chu@oracle.com
Fixes: 05ea886 ("mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct")
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

RDMA/core: Avoid that ib_drain_qp() triggers an out-of-bounds stack a…
…ccess

commit a1ae7d0 upstream.

This patch fixes the following KASAN complaint:

==================================================================
BUG: KASAN: stack-out-of-bounds in rxe_post_send+0x77d/0x9b0 [rdma_rxe]
Read of size 8 at addr ffff880061aef860 by task 01/1080

CPU: 2 PID: 1080 Comm: 01 Not tainted 4.16.0-rc3-dbg+ #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014
Call Trace:
dump_stack+0x85/0xc7
print_address_description+0x65/0x270
kasan_report+0x231/0x350
rxe_post_send+0x77d/0x9b0 [rdma_rxe]
__ib_drain_sq+0x1ad/0x250 [ib_core]
ib_drain_qp+0x9/0x30 [ib_core]
srp_destroy_qp+0x51/0x70 [ib_srp]
srp_free_ch_ib+0xfc/0x380 [ib_srp]
srp_create_target+0x1071/0x19e0 [ib_srp]
kernfs_fop_write+0x180/0x210
__vfs_write+0xb1/0x2e0
vfs_write+0xf6/0x250
SyS_write+0x99/0x110
do_syscall_64+0xee/0x2b0
entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the page:
page:ffffea000186bbc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x4000000000000000()
raw: 4000000000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 ffffea000186bbe0 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff880061aef700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff880061aef780: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
>ffff880061aef800: f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 f2 f2 f2 f2
                                                      ^
ffff880061aef880: f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 f2 f2
ffff880061aef900: f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Fixes: 765d677 ("IB: new common API for draining queues")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: stable@vger.kernel.org
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

kernel/hung_task.c: show all hung tasks before panic
[ Upstream commit 401c636 ]

When we get a hung task it can often be valuable to see _all_ the hung
tasks on the system before calling panic().

Quoting from https://syzkaller.appspot.com/text?tag=CrashReport&id=5316056503549952
----------------------------------------
INFO: task syz-executor0:6540 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D23560  6540   4521 0x80000004
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x8fb/0x1ef0 kernel/sched/core.c:3490
 schedule+0xf5/0x430 kernel/sched/core.c:3549
 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3607
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0xb7f/0x1810 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601
 ioctl_by_bdev+0xa5/0x110 fs/block_dev.c:2060
 isofs_get_last_session fs/isofs/inode.c:567 [inline]
 isofs_fill_super+0x2ba9/0x3bc0 fs/isofs/inode.c:660
 mount_bdev+0x2b7/0x370 fs/super.c:1119
 isofs_mount+0x34/0x40 fs/isofs/inode.c:1560
 mount_fs+0x66/0x2d0 fs/super.c:1222
 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:2514 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0xea4/0x2b90 fs/namespace.c:2847
 ksys_mount+0xab/0x120 fs/namespace.c:3063
 SYSC_mount fs/namespace.c:3077 [inline]
 SyS_mount+0x39/0x50 fs/namespace.c:3074
 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
(...snipped...)
Showing all locks held in the system:
(...snipped...)
2 locks held by syz-executor0/6540:
 #0: 00000000566d4c39 (&type->s_umount_key#49/1){+.+.}, at: alloc_super fs/super.c:211 [inline]
 #0: 00000000566d4c39 (&type->s_umount_key#49/1){+.+.}, at: sget_userns+0x3b2/0xe60 fs/super.c:502 /* down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); */
 #1: 0000000043ca8836 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 /* mutex_lock_nested(&lo->lo_ctl_mutex, 1); */
(...snipped...)
3 locks held by syz-executor7/6541:
 #0: 0000000043ca8836 (&lo->lo_ctl_mutex/1){+.+.}, at: lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 /* mutex_lock_nested(&lo->lo_ctl_mutex, 1); */
 #1: 000000007bf3d3f9 (&bdev->bd_mutex){+.+.}, at: blkdev_reread_part+0x1e/0x40 block/ioctl.c:192
 #2: 00000000566d4c39 (&type->s_umount_key#50){.+.+}, at: __get_super.part.10+0x1d3/0x280 fs/super.c:663 /* down_read(&sb->s_umount); */
----------------------------------------

When reporting an AB-BA deadlock like shown above, it would be nice if
trace of PID=6541 is printed as well as trace of PID=6540 before calling
panic().

Showing hung tasks up to /proc/sys/kernel/hung_task_warnings could delay
calling panic() but normally there should not be so many hung tasks.

Link: http://lkml.kernel.org/r/201804050705.BHE57833.HVFOFtSOMQJFOL@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

scsi: qedf: Set the UNLOADING flag when removing a vport
[ Upstream commit 4f4616c ]

Similar to what we do when we remove a PCI function, set the
QEDF_UNLOADING flag to prevent any requests from being queued while a
vport is being deleted.  This prevents any requests from getting stuck
in limbo when the vport is unloaded or deleted.

Fixes the crash:

PID: 106676  TASK: ffff9a436aa90000  CPU: 12  COMMAND: "multipathd"
 #0 [ffff9a43567d3550] machine_kexec+522 at ffffffffaca60b2a
 #1 [ffff9a43567d35b0] __crash_kexec+114 at ffffffffacb13512
 #2 [ffff9a43567d3680] crash_kexec+48 at ffffffffacb13600
 #3 [ffff9a43567d3698] oops_end+168 at ffffffffad117768
 #4 [ffff9a43567d36c0] no_context+645 at ffffffffad106f52
 #5 [ffff9a43567d3710] __bad_area_nosemaphore+116 at ffffffffad106fe9
 #6 [ffff9a43567d3760] bad_area+70 at ffffffffad107379
 #7 [ffff9a43567d3788] __do_page_fault+1247 at ffffffffad11a8cf
 #8 [ffff9a43567d37f0] do_page_fault+53 at ffffffffad11a915
 #9 [ffff9a43567d3820] page_fault+40 at ffffffffad116768
    [exception RIP: qedf_init_task+61]
    RIP: ffffffffc0e13c2d  RSP: ffff9a43567d38d0  RFLAGS: 00010046
    RAX: 0000000000000000  RBX: ffffbe920472c738  RCX: ffff9a434fa0e3e8
    RDX: ffff9a434f695280  RSI: ffffbe920472c738  RDI: ffff9a43aa359c80
    RBP: ffff9a43567d3950   R8: 0000000000000c15   R9: ffff9a3fb09b9880
    R10: ffff9a434fa0e3e8  R11: ffff9a43567d35ce  R12: 0000000000000000
    R13: ffff9a434f695280  R14: ffff9a43aa359c80  R15: ffff9a3fb9e005c0
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018

Signed-off-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

bonding: avoid lockdep confusion in bond_get_stats()
[ Upstream commit 7e2556e40026a1b0c16f37446ab398d5a5a892e4 ]

syzbot found that the following sequence produces a LOCKDEP splat [1]

ip link add bond10 type bond
ip link add bond11 type bond
ip link set bond11 master bond10

To fix this, we can use the already provided nest_level.

This patch also provides correct nesting for dev->addr_list_lock

[1]
WARNING: possible recursive locking detected
4.18.0-rc6+ #167 Not tainted
--------------------------------------------
syz-executor751/4439 is trying to acquire lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

but task is already holding lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&bond->stats_lock)->rlock);
  lock(&(&bond->stats_lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor751/4439:
 #0: (____ptrval____) (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 #2: (____ptrval____) (rcu_read_lock){....}, at: bond_get_stats+0x0/0x560 include/linux/compiler.h:215

stack backtrace:
CPU: 0 PID: 4439 Comm: syz-executor751 Not tainted 4.18.0-rc6+ #167
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_deadlock_bug kernel/locking/lockdep.c:1765 [inline]
 check_deadlock kernel/locking/lockdep.c:1809 [inline]
 validate_chain kernel/locking/lockdep.c:2405 [inline]
 __lock_acquire.cold.64+0x1fb/0x486 kernel/locking/lockdep.c:3435
 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
 spin_lock include/linux/spinlock.h:310 [inline]
 bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 bond_get_stats+0x232/0x560 drivers/net/bonding/bond_main.c:3432
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 rtnl_fill_stats+0x4d/0xac0 net/core/rtnetlink.c:1169
 rtnl_fill_ifinfo+0x1aa6/0x3fb0 net/core/rtnetlink.c:1611
 rtmsg_ifinfo_build_skb+0xc8/0x190 net/core/rtnetlink.c:3268
 rtmsg_ifinfo_event.part.30+0x45/0xe0 net/core/rtnetlink.c:3300
 rtmsg_ifinfo_event net/core/rtnetlink.c:3297 [inline]
 rtnetlink_event+0x144/0x170 net/core/rtnetlink.c:4716
 notifier_call_chain+0x180/0x390 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1735
 call_netdevice_notifiers net/core/dev.c:1753 [inline]
 netdev_features_change net/core/dev.c:1321 [inline]
 netdev_change_features+0xb3/0x110 net/core/dev.c:7759
 bond_compute_features.isra.47+0x585/0xa50 drivers/net/bonding/bond_main.c:1120
 bond_enslave+0x1b25/0x5da0 drivers/net/bonding/bond_main.c:1755
 bond_do_ioctl+0x7cb/0xae0 drivers/net/bonding/bond_main.c:3528
 dev_ifsioc+0x43c/0xb30 net/core/dev_ioctl.c:327
 dev_ioctl+0x1b5/0xcc0 net/core/dev_ioctl.c:493
 sock_do_ioctl+0x1d3/0x3e0 net/socket.c:992
 sock_ioctl+0x30d/0x680 net/socket.c:1093
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440859
Code: e8 2c af 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc51a92878 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440859
RDX: 0000000020000040 RSI: 0000000000008990 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000022d5880 R11: 0000000000000213 R12: 0000000000007390
R13: 0000000000401db0 R14: 0000000000000000 R15: 0000000000000000

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 7, 2018

virtio_balloon: fix another race between migration and ballooning
commit 89da619bc18d79bca5304724c11d4ba3b67ce2c6 upstream.

Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: stable@vger.kernel.org
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Huang Chong <huang.chong@zte.com.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

Vincent Whitchurch Russell King
ARM: 8781/1: Fix Thumb-2 syscall return for binutils 2.29+
When building the kernel as Thumb-2 with binutils 2.29 or newer, if the
assembler has seen the .type directive (via ENDPROC()) for a symbol, it
automatically handles the setting of the lowest bit when the symbol is
used with ADR.  The badr macro on the other hand handles this lowest bit
manually.  This leads to a jump to a wrong address in the wrong state
in the syscall return path:

 Internal error: Oops - undefined instruction: 0 [#2] SMP THUMB2
 Modules linked in:
 CPU: 0 PID: 652 Comm: modprobe Tainted: G      D           4.18.0-rc3+ #8
 PC is at ret_fast_syscall+0x4/0x62
 LR is at sys_brk+0x109/0x128
 pc : [<80101004>]    lr : [<801c8a35>]    psr: 60000013
 Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
 Control: 50c5387d  Table: 9e82006a  DAC: 00000051
 Process modprobe (pid: 652, stack limit = 0x(ptrval))

 80101000 <ret_fast_syscall>:
 80101000:       b672            cpsid   i
 80101002:       f8d9 2008       ldr.w   r2, [r9, #8]
 80101006:       f1b2 4ffe       cmp.w   r2, #2130706432 ; 0x7f000000

 80101184 <local_restart>:
 80101184:       f8d9 a000       ldr.w   sl, [r9]
 80101188:       e92d 0030       stmdb   sp!, {r4, r5}
 8010118c:       f01a 0ff0       tst.w   sl, #240        ; 0xf0
 80101190:       d117            bne.n   801011c2 <__sys_trace>
 80101192:       46ba            mov     sl, r7
 80101194:       f5ba 7fc8       cmp.w   sl, #400        ; 0x190
 80101198:       bf28            it      cs
 8010119a:       f04f 0a00       movcs.w sl, #0
 8010119e:       f3af 8014       nop.w   {20}
 801011a2:       f2af 1ea2       subw    lr, pc, #418    ; 0x1a2

To fix this, add a new symbol name which doesn't have ENDPROC used on it
and use that with badr.  We can't remove the badr usage since that would
would cause breakage with older binutils.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

virtio_balloon: fix another race between migration and ballooning
Kernel panic when with high memory pressure, calltrace looks like,

PID: 21439 TASK: ffff881be3afedd0 CPU: 16 COMMAND: "java"
 #0 [ffff881ec7ed7630] machine_kexec at ffffffff81059beb
 #1 [ffff881ec7ed7690] __crash_kexec at ffffffff81105942
 #2 [ffff881ec7ed7760] crash_kexec at ffffffff81105a30
 #3 [ffff881ec7ed7778] oops_end at ffffffff816902c8
 #4 [ffff881ec7ed77a0] no_context at ffffffff8167ff46
 #5 [ffff881ec7ed77f0] __bad_area_nosemaphore at ffffffff8167ffdc
 #6 [ffff881ec7ed7838] __node_set at ffffffff81680300
 #7 [ffff881ec7ed7860] __do_page_fault at ffffffff8169320f
 #8 [ffff881ec7ed78c0] do_page_fault at ffffffff816932b5
 #9 [ffff881ec7ed78f0] page_fault at ffffffff8168f4c8
    [exception RIP: _raw_spin_lock_irqsave+47]
    RIP: ffffffff8168edef RSP: ffff881ec7ed79a8 RFLAGS: 00010046
    RAX: 0000000000000246 RBX: ffffea0019740d00 RCX: ffff881ec7ed7fd8
    RDX: 0000000000020000 RSI: 0000000000000016 RDI: 0000000000000008
    RBP: ffff881ec7ed79a8 R8: 0000000000000246 R9: 000000000001a098
    R10: ffff88107ffda000 R11: 0000000000000000 R12: 0000000000000000
    R13: 0000000000000008 R14: ffff881ec7ed7a80 R15: ffff881be3afedd0
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018

It happens in the pagefault and results in double pagefault
during compacting pages when memory allocation fails.

Analysed the vmcore, the page leads to second pagefault is corrupted
with _mapcount=-256, but private=0.

It's caused by the race between migration and ballooning, and lock
missing in virtballoon_migratepage() of virtio_balloon driver.
This patch fix the bug.

Fixes: e225042 ("virtio_balloon: introduce migration primitives to balloon pages")
Cc: stable@vger.kernel.org
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Signed-off-by: Huang Chong <huang.chong@zte.com.cn>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

bonding: avoid lockdep confusion in bond_get_stats()
syzbot found that the following sequence produces a LOCKDEP splat [1]

ip link add bond10 type bond
ip link add bond11 type bond
ip link set bond11 master bond10

To fix this, we can use the already provided nest_level.

This patch also provides correct nesting for dev->addr_list_lock

[1]
WARNING: possible recursive locking detected
4.18.0-rc6+ #167 Not tainted
--------------------------------------------
syz-executor751/4439 is trying to acquire lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

but task is already holding lock:
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
(____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&bond->stats_lock)->rlock);
  lock(&(&bond->stats_lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz-executor751/4439:
 #0: (____ptrval____) (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:77
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:310 [inline]
 #1: (____ptrval____) (&(&bond->stats_lock)->rlock){+.+.}, at: bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 #2: (____ptrval____) (rcu_read_lock){....}, at: bond_get_stats+0x0/0x560 include/linux/compiler.h:215

stack backtrace:
CPU: 0 PID: 4439 Comm: syz-executor751 Not tainted 4.18.0-rc6+ #167
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_deadlock_bug kernel/locking/lockdep.c:1765 [inline]
 check_deadlock kernel/locking/lockdep.c:1809 [inline]
 validate_chain kernel/locking/lockdep.c:2405 [inline]
 __lock_acquire.cold.64+0x1fb/0x486 kernel/locking/lockdep.c:3435
 lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
 spin_lock include/linux/spinlock.h:310 [inline]
 bond_get_stats+0xb4/0x560 drivers/net/bonding/bond_main.c:3426
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 bond_get_stats+0x232/0x560 drivers/net/bonding/bond_main.c:3432
 dev_get_stats+0x10f/0x470 net/core/dev.c:8316
 rtnl_fill_stats+0x4d/0xac0 net/core/rtnetlink.c:1169
 rtnl_fill_ifinfo+0x1aa6/0x3fb0 net/core/rtnetlink.c:1611
 rtmsg_ifinfo_build_skb+0xc8/0x190 net/core/rtnetlink.c:3268
 rtmsg_ifinfo_event.part.30+0x45/0xe0 net/core/rtnetlink.c:3300
 rtmsg_ifinfo_event net/core/rtnetlink.c:3297 [inline]
 rtnetlink_event+0x144/0x170 net/core/rtnetlink.c:4716
 notifier_call_chain+0x180/0x390 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1735
 call_netdevice_notifiers net/core/dev.c:1753 [inline]
 netdev_features_change net/core/dev.c:1321 [inline]
 netdev_change_features+0xb3/0x110 net/core/dev.c:7759
 bond_compute_features.isra.47+0x585/0xa50 drivers/net/bonding/bond_main.c:1120
 bond_enslave+0x1b25/0x5da0 drivers/net/bonding/bond_main.c:1755
 bond_do_ioctl+0x7cb/0xae0 drivers/net/bonding/bond_main.c:3528
 dev_ifsioc+0x43c/0xb30 net/core/dev_ioctl.c:327
 dev_ioctl+0x1b5/0xcc0 net/core/dev_ioctl.c:493
 sock_do_ioctl+0x1d3/0x3e0 net/socket.c:992
 sock_ioctl+0x30d/0x680 net/socket.c:1093
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:684
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
 __do_sys_ioctl fs/ioctl.c:708 [inline]
 __se_sys_ioctl fs/ioctl.c:706 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:706
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440859
Code: e8 2c af 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc51a92878 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440859
RDX: 0000000020000040 RSI: 0000000000008990 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000022d5880 R11: 0000000000000213 R12: 0000000000007390
R13: 0000000000401db0 R14: 0000000000000000 R15: 0000000000000000

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>

Signed-off-by: David S. Miller <davem@davemloft.net>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

staging: ashmem: Fix SIGBUS crash when traversing mmaped ashmem pages
Amit Pundir and Youling in parallel reported crashes with recent
mainline kernels running Android:

  F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
  F DEBUG   : Build fingerprint: 'Android/db410c32_only/db410c32_only:Q/OC-MR1/102:userdebug/test-key
  F DEBUG   : Revision: '0'
  F DEBUG   : ABI: 'arm'
  F DEBUG   : pid: 2261, tid: 2261, name: zygote  >>> zygote <<<
  F DEBUG   : signal 7 (SIGBUS), code 2 (BUS_ADRERR), fault addr 0xec00008
  ... <snip> ...
  F DEBUG   : backtrace:
  F DEBUG   :     #00 pc 00001c04  /system/lib/libc.so (memset+48)
  F DEBUG   :     #1 pc 0010c513  /system/lib/libart.so (create_mspace_with_base+82)
  F DEBUG   :     #2 pc 0015c601  /system/lib/libart.so (art::gc::space::DlMallocSpace::CreateMspace(void*, unsigned int, unsigned int)+40)
  F DEBUG   :     #3 pc 0015c3ed  /system/lib/libart.so (art::gc::space::DlMallocSpace::CreateFromMemMap(art::MemMap*, std::__1::basic_string<char, std::__ 1::char_traits<char>, std::__1::allocator<char>> const&, unsigned int, unsigned int, unsigned int, unsigned int, bool)+36)
  ...

This was bisected back to commit bfd40ea ("mm: fix
vma_is_anonymous() false-positives").

create_mspace_with_base() in the trace above, utilizes ashmem, and with
ashmem, for shared mappings we use shmem_zero_setup(), which sets the
vma->vm_ops to &shmem_vm_ops.  But for private ashmem mappings nothing
sets the vma->vm_ops.

Looking at the problematic patch, it seems to add a requirement that one
call vma_set_anonymous() on a vma, otherwise the dummy_vm_ops will be
used.  Using the dummy_vm_ops seem to triggger SIGBUS when traversing
unmapped pages.

Thus, this patch adds a call to vma_set_anonymous() for ashmem private
mappings and seems to avoid the reported problem.

Fixes: bfd40ea ("mm: fix vma_is_anonymous() false-positives")
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Colin Cross <ccross@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Reported-by: Amit Pundir <amit.pundir@linaro.org>
Reported-by: Youling 257 <youling257@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

ipc/shm.c add ->pagesize function to shm_vm_ops
Commit 05ea886 ("mm, hugetlbfs: introduce ->pagesize() to
vm_operations_struct") adds a new ->pagesize() function to
hugetlb_vm_ops, intended to cover all hugetlbfs backed files.

With System V shared memory model, if "huge page" is specified, the
"shared memory" is backed by hugetlbfs files, but the mappings initiated
via shmget/shmat have their original vm_ops overwritten with shm_vm_ops,
so we need to add a ->pagesize function to shm_vm_ops.  Otherwise,
vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs backed vma,
result in below BUG:

  fs/hugetlbfs/inode.c
        443             if (unlikely(page_mapped(page))) {
        444                     BUG_ON(truncate_op);

resulting in

  hugetlbfs: oracle (4592): Using mlock ulimits for SHM_HUGETLB is deprecated
  ------------[ cut here ]------------
  kernel BUG at fs/hugetlbfs/inode.c:444!
  Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 ...
  CPU: 35 PID: 5583 Comm: oracle_5583_sbt Not tainted 4.14.35-1829.el7uek.x86_64 #2
  RIP: 0010:remove_inode_hugepages+0x3db/0x3e2
  ....
  Call Trace:
    hugetlbfs_evict_inode+0x1e/0x3e
    evict+0xdb/0x1af
    iput+0x1a2/0x1f7
    dentry_unlink_inode+0xc6/0xf0
    __dentry_kill+0xd8/0x18d
    dput+0x1b5/0x1ed
    __fput+0x18b/0x216
    ____fput+0xe/0x10
    task_work_run+0x90/0xa7
    exit_to_usermode_loop+0xdd/0x116
    do_syscall_64+0x187/0x1ae
    entry_SYSCALL_64_after_hwframe+0x150/0x0

[jane.chu@oracle.com: relocate comment]
  Link: http://lkml.kernel.org/r/20180731044831.26036-1-jane.chu@oracle.com
Link: http://lkml.kernel.org/r/20180727211727.5020-1-jane.chu@oracle.com
Fixes: 05ea886 ("mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct")
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

rxrpc: Fix the keepalive generator [ver #2]
AF_RXRPC has a keepalive message generator that generates a message for a
peer ~20s after the last transmission to that peer to keep firewall ports
open.  The implementation is incorrect in the following ways:

 (1) It mixes up ktime_t and time64_t types.

 (2) It uses ktime_get_real(), the output of which may jump forward or
     backward due to adjustments to the time of day.

 (3) If the current time jumps forward too much or jumps backwards, the
     generator function will crank the base of the time ring round one slot
     at a time (ie. a 1s period) until it catches up, spewing out VERSION
     packets as it goes.

Fix the problem by:

 (1) Only using time64_t.  There's no need for sub-second resolution.

 (2) Use ktime_get_seconds() rather than ktime_get_real() so that time
     isn't perceived to go backwards.

 (3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two
     parts:

     (a) The "worker" function that manages the buckets and the timer.

     (b) The "dispatch" function that takes the pending peers and
     	 potentially transmits a keepalive packet before putting them back
     	 in the ring into the slot appropriate to the revised last-Tx time.

 (4) Taking everything that's pending out of the ring and splicing it into
     a temporary collector list for processing.

     In the case that there's been a significant jump forward, the ring
     gets entirely emptied and then the time base can be warped forward
     before the peers are processed.

     The warping can't happen if the ring isn't empty because the slot a
     peer is in is keepalive-time dependent, relative to the base time.

 (5) Limit the number of iterations of the bucket array when scanning it.

 (6) Set the timer to skip any empty slots as there's no point waking up if
     there's nothing to do yet.

This can be triggered by an incoming call from a server after a reboot with
AF_RXRPC and AFS built into the kernel causing a peer record to be set up
before userspace is started.  The system clock is then adjusted by
userspace, thereby potentially causing the keepalive generator to have a
meltdown - which leads to a message like:

	watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23]
	...
	Workqueue: krxrpcd rxrpc_peer_keepalive_worker
	EIP: lock_acquire+0x69/0x80
	...
	Call Trace:
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? _raw_spin_lock_bh+0x29/0x60
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? rxrpc_peer_keepalive_worker+0x5e/0x350
	 ? __lock_acquire+0x3d3/0x870
	 ? process_one_work+0x110/0x340
	 ? process_one_work+0x166/0x340
	 ? process_one_work+0x110/0x340
	 ? worker_thread+0x39/0x3c0
	 ? kthread+0xdb/0x110
	 ? cancel_delayed_work+0x90/0x90
	 ? kthread_stop+0x70/0x70
	 ? ret_from_fork+0x19/0x24

Fixes: ace45be ("rxrpc: Fix firewall route keepalive")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

popcornmix pushed a commit that referenced this issue Aug 14, 2018

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) The real fix for the ipv6 route metric leak Sabrina was seeing, from
    Cong Wang.

 2) Fix syzbot triggers AF_PACKET v3 ring buffer insufficient room
    conditions, from Willem de Bruijn.

 3) vsock can reinitialize active work struct, fix from Cong Wang.

 4) RXRPC keepalive generator can wedge a cpu, fix from David Howells.

 5) Fix locking in AF_SMC ioctl, from Ursula Braun.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  dsa: slave: eee: Allow ports to use phylink
  net/smc: move sock lock in smc_ioctl()
  net/smc: allow sysctl rmem and wmem defaults for servers
  net/smc: no shutdown in state SMC_LISTEN
  net: aquantia: Fix IFF_ALLMULTI flag functionality
  rxrpc: Fix the keepalive generator [ver #2]
  net/mlx5e: Cleanup of dcbnl related fields
  net/mlx5e: Properly check if hairpin is possible between two functions
  vhost: reset metadata cache when initializing new IOTLB
  llc: use refcount_inc_not_zero() for llc_sap_find()
  dccp: fix undefined behavior with 'cwnd' shift in ccid2_cwnd_restart()
  tipc: fix an interrupt unsafe locking scenario
  vsock: split dwork to avoid reinitializations
  net: thunderx: check for failed allocation lmac->dmacs
  cxgb4: mk_act_open_req() buggers ->{local, peer}_ip on big-endian hosts
  packet: refine ring v3 block size test to hold one frame
  ip6_tunnel: use the right value for ipv4 min mtu check in ip6_tnl_xmit
  ipv6: fix double refcount of fib6_metrics
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