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Feedback from check tool #7

Merged
2 commits merged into from
May 4, 2016
Merged

Feedback from check tool #7

2 commits merged into from
May 4, 2016

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jenswi-linaro
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Corrections based on output from tool provided by Nishanth Menon at
https://github.com/nmenon/kernel_patch_verify

These patches will be included in the coming v10 patch set.

struct mutex mu;
struct list_head db;
};

/**
* struct optee_supp - supplicant synchronization struct
* @func: supplicant function id to call

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missing available

@pascal-brand38
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With or without my comments:
Reviewed-by: Pascal Brand <pascal.brand@linaro.org>

@jenswi-linaro
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Update

@pascal-brand38
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Reviewed-by: Pascal Brand <pascal.brand@linaro.org>

Corrections based on output from tool provided by Nishanth Menon at
https://github.com/nmenon/kernel_patch_verify

The patch will merged into the "tee: add OP-TEE driver" commit
when creating the v10 patch set.

Reviewed-by: Pascal Brand <pascal.brand@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Corrections based on output from tool provided by Nishanth Menon at
https://github.com/nmenon/kernel_patch_verify

The patch will merged into the "tee: generic TEE subsystem" commit
when creating the v10 patch set.

Reviewed-by: Pascal Brand <pascal.brand@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
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Tag applied

@ghost ghost merged commit d84b0fb into linaro-swg:optee May 4, 2016
@jenswi-linaro jenswi-linaro deleted the feedback branch May 4, 2016 07:12
showliu pushed a commit to showliu/linux that referenced this pull request Jun 16, 2016
commit ec183d2 upstream.

Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  linaro-swg#1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  linaro-swg#2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  linaro-swg#3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  linaro-swg#4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  linaro-swg#5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  linaro-swg#6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  linaro-swg#7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  linaro-swg#8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  linaro-swg#9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  linaro-swg#10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  linaro-swg#11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  linaro-swg#12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  linaro-swg#13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  linaro-swg#14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  linaro-swg#15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Tong Zhang <ztong@vt.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/1453809921-24596-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
showliu pushed a commit to showliu/linux that referenced this pull request Jun 16, 2016
commit 17e4bce upstream.

Ubsan reports the following warning due to a typo in
update_accessed_dirty_bits template, the patch fixes
the typo:

[  168.791851] ================================================================================
[  168.791862] UBSAN: Undefined behaviour in arch/x86/kvm/paging_tmpl.h:252:15
[  168.791866] index 4 is out of range for type 'u64 [4]'
[  168.791871] CPU: 0 PID: 2950 Comm: qemu-system-x86 Tainted: G           O L  4.5.0-rc5-next-20160222 linaro-swg#7
[  168.791873] Hardware name: LENOVO 23205NG/23205NG, BIOS G2ET95WW (2.55 ) 07/09/2013
[  168.791876]  0000000000000000 ffff8801cfcaf208 ffffffff81c9f780 0000000041b58ab3
[  168.791882]  ffffffff82eb2cc1 ffffffff81c9f6b4 ffff8801cfcaf230 ffff8801cfcaf1e0
[  168.791886]  0000000000000004 0000000000000001 0000000000000000 ffffffffa1981600
[  168.791891] Call Trace:
[  168.791899]  [<ffffffff81c9f780>] dump_stack+0xcc/0x12c
[  168.791904]  [<ffffffff81c9f6b4>] ? _atomic_dec_and_lock+0xc4/0xc4
[  168.791910]  [<ffffffff81da9e81>] ubsan_epilogue+0xd/0x8a
[  168.791914]  [<ffffffff81daafa2>] __ubsan_handle_out_of_bounds+0x15c/0x1a3
[  168.791918]  [<ffffffff81daae46>] ? __ubsan_handle_shift_out_of_bounds+0x2bd/0x2bd
[  168.791922]  [<ffffffff811287ef>] ? get_user_pages_fast+0x2bf/0x360
[  168.791954]  [<ffffffffa1794050>] ? kvm_largepages_enabled+0x30/0x30 [kvm]
[  168.791958]  [<ffffffff81128530>] ? __get_user_pages_fast+0x360/0x360
[  168.791987]  [<ffffffffa181b818>] paging64_walk_addr_generic+0x1b28/0x2600 [kvm]
[  168.792014]  [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm]
[  168.792019]  [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350
[  168.792044]  [<ffffffffa1819cf0>] ? init_kvm_mmu+0x1100/0x1100 [kvm]
[  168.792076]  [<ffffffffa181c36d>] paging64_gva_to_gpa+0x7d/0x110 [kvm]
[  168.792121]  [<ffffffffa181c2f0>] ? paging64_walk_addr_generic+0x2600/0x2600 [kvm]
[  168.792130]  [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90
[  168.792178]  [<ffffffffa17d9a4a>] emulator_read_write_onepage+0x27a/0x1150 [kvm]
[  168.792208]  [<ffffffffa1794d44>] ? __kvm_read_guest_page+0x54/0x70 [kvm]
[  168.792234]  [<ffffffffa17d97d0>] ? kvm_task_switch+0x160/0x160 [kvm]
[  168.792238]  [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90
[  168.792263]  [<ffffffffa17daa07>] emulator_read_write+0xe7/0x6d0 [kvm]
[  168.792290]  [<ffffffffa183b620>] ? em_cr_write+0x230/0x230 [kvm]
[  168.792314]  [<ffffffffa17db005>] emulator_write_emulated+0x15/0x20 [kvm]
[  168.792340]  [<ffffffffa18465f8>] segmented_write+0xf8/0x130 [kvm]
[  168.792367]  [<ffffffffa1846500>] ? em_lgdt+0x20/0x20 [kvm]
[  168.792374]  [<ffffffffa14db512>] ? vmx_read_guest_seg_ar+0x42/0x1e0 [kvm_intel]
[  168.792400]  [<ffffffffa1846d82>] writeback+0x3f2/0x700 [kvm]
[  168.792424]  [<ffffffffa1846990>] ? em_sidt+0xa0/0xa0 [kvm]
[  168.792449]  [<ffffffffa185554d>] ? x86_decode_insn+0x1b3d/0x4f70 [kvm]
[  168.792474]  [<ffffffffa1859032>] x86_emulate_insn+0x572/0x3010 [kvm]
[  168.792499]  [<ffffffffa17e71dd>] x86_emulate_instruction+0x3bd/0x2110 [kvm]
[  168.792524]  [<ffffffffa17e6e20>] ? reexecute_instruction.part.110+0x2e0/0x2e0 [kvm]
[  168.792532]  [<ffffffffa14e9a81>] handle_ept_misconfig+0x61/0x460 [kvm_intel]
[  168.792539]  [<ffffffffa14e9a20>] ? handle_pause+0x450/0x450 [kvm_intel]
[  168.792546]  [<ffffffffa15130ea>] vmx_handle_exit+0xd6a/0x1ad0 [kvm_intel]
[  168.792572]  [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm]
[  168.792597]  [<ffffffffa17f6bcd>] kvm_arch_vcpu_ioctl_run+0xd3d/0x6090 [kvm]
[  168.792621]  [<ffffffffa17f6a6c>] ? kvm_arch_vcpu_ioctl_run+0xbdc/0x6090 [kvm]
[  168.792627]  [<ffffffff8293b530>] ? __ww_mutex_lock_interruptible+0x1630/0x1630
[  168.792651]  [<ffffffffa17f5e90>] ? kvm_arch_vcpu_runnable+0x4f0/0x4f0 [kvm]
[  168.792656]  [<ffffffff811eeb30>] ? preempt_notifier_unregister+0x190/0x190
[  168.792681]  [<ffffffffa17e0447>] ? kvm_arch_vcpu_load+0x127/0x650 [kvm]
[  168.792704]  [<ffffffffa178e9a3>] kvm_vcpu_ioctl+0x553/0xda0 [kvm]
[  168.792727]  [<ffffffffa178e450>] ? vcpu_put+0x40/0x40 [kvm]
[  168.792732]  [<ffffffff8129e350>] ? debug_check_no_locks_freed+0x350/0x350
[  168.792735]  [<ffffffff82946087>] ? _raw_spin_unlock+0x27/0x40
[  168.792740]  [<ffffffff8163a943>] ? handle_mm_fault+0x1673/0x2e40
[  168.792744]  [<ffffffff8129daa8>] ? trace_hardirqs_on_caller+0x478/0x6c0
[  168.792747]  [<ffffffff8129dcfd>] ? trace_hardirqs_on+0xd/0x10
[  168.792751]  [<ffffffff812e848b>] ? debug_lockdep_rcu_enabled+0x7b/0x90
[  168.792756]  [<ffffffff81725a80>] do_vfs_ioctl+0x1b0/0x12b0
[  168.792759]  [<ffffffff817258d0>] ? ioctl_preallocate+0x210/0x210
[  168.792763]  [<ffffffff8174aef3>] ? __fget+0x273/0x4a0
[  168.792766]  [<ffffffff8174acd0>] ? __fget+0x50/0x4a0
[  168.792770]  [<ffffffff8174b1f6>] ? __fget_light+0x96/0x2b0
[  168.792773]  [<ffffffff81726bf9>] SyS_ioctl+0x79/0x90
[  168.792777]  [<ffffffff82946880>] entry_SYSCALL_64_fastpath+0x23/0xc1
[  168.792780] ================================================================================

Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Feb 24, 2017
commit a782b5f upstream.

Previously we checked for iATU unroll support by reading PCIE_ATU_VIEWPORT
even on platforms, e.g., Keystone, that do not have ATU ports.  This can
cause bad behavior such as asynchronous external aborts:

  OF: PCI:   MEM 0x60000000..0x6fffffff -> 0x60000000
  Unhandled fault: asynchronous external abort (0x1211) at 0x00000000
  pgd = c0003000
  [00000000] *pgd=80000800004003, *pmd=00000000
  Internal error: : 1211 [#1] PREEMPT SMP ARM
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-00009-g6ff59d2-dirty #7
  Hardware name: Keystone
  task: eb878000 task.stack: eb866000
  PC is at dw_pcie_setup_rc+0x24/0x380
  LR is at ks_pcie_host_init+0x10/0x170

Move the dw_pcie_iatu_unroll_enabled() check so we only call it on
platforms that do not use the ATU.  These platforms supply their own
->rd_other_conf() and ->wr_other_conf() methods.

[bhelgaas: changelog]
Fixes: a0601a4 ("PCI: designware: Add iATU Unroll feature")
Fixes: 416379f ("PCI: designware: Check for iATU unroll support after initializing host")
Tested-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-By: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
etienne-lms pushed a commit to etienne-lms/linux that referenced this pull request Sep 14, 2017
commit cdea465 upstream.

A vendor with a system having more than 128 CPUs occasionally encounters
the following crash during shutdown. This is not an easily reproduceable
event, but the vendor was able to provide the following analysis of the
crash, which exhibits the same footprint each time.

crash> bt
PID: 0      TASK: ffff88017c70ce70  CPU: 5   COMMAND: "swapper/5"
 #0 [ffff88085c143ac8] machine_kexec at ffffffff81059c8b
 #1 [ffff88085c143b28] __crash_kexec at ffffffff811052e2
 #2 [ffff88085c143bf8] crash_kexec at ffffffff811053d0
 linaro-swg#3 [ffff88085c143c10] oops_end at ffffffff8168ef88
 linaro-swg#4 [ffff88085c143c38] no_context at ffffffff8167ebb3
 linaro-swg#5 [ffff88085c143c88] __bad_area_nosemaphore at ffffffff8167ec49
 linaro-swg#6 [ffff88085c143cd0] bad_area_nosemaphore at ffffffff8167edb3
 linaro-swg#7 [ffff88085c143ce0] __do_page_fault at ffffffff81691d1e
 linaro-swg#8 [ffff88085c143d40] do_page_fault at ffffffff81691ec5
 linaro-swg#9 [ffff88085c143d70] page_fault at ffffffff8168e188
    [exception RIP: unknown or invalid address]
    RIP: ffffffffa053c800  RSP: ffff88085c143e28  RFLAGS: 00010206
    RAX: ffff88017c72bfd8  RBX: ffff88017a8dc000  RCX: ffff8810588b5ac8
    RDX: ffff8810588b5a00  RSI: ffffffffa053c800  RDI: ffff8810588b5a00
    RBP: ffff88085c143e58   R8: ffff88017c70d408   R9: ffff88017a8dc000
    R10: 0000000000000002  R11: ffff88085c143da0  R12: ffff8810588b5ac8
    R13: 0000000000000100  R14: ffffffffa053c800  R15: ffff8810588b5a00
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
    <IRQ stack>
    [exception RIP: cpuidle_enter_state+82]
    RIP: ffffffff81514192  RSP: ffff88017c72be50  RFLAGS: 00000202
    RAX: 0000001e4c3c6f16  RBX: 000000000000f8a0  RCX: 0000000000000018
    RDX: 0000000225c17d03  RSI: ffff88017c72bfd8  RDI: 0000001e4c3c6f16
    RBP: ffff88017c72be78   R8: 000000000000237e   R9: 0000000000000018
    R10: 0000000000002494  R11: 0000000000000001  R12: ffff88017c72be20
    R13: ffff88085c14f8e0  R14: 0000000000000082  R15: 0000001e4c3bb400
    ORIG_RAX: ffffffffffffff10  CS: 0010  SS: 0018

This is the corresponding stack trace

It has crashed because the area pointed with RIP extracted from timer
element is already removed during a shutdown process.

The function is smi_timeout().

And we think ffff8810588b5a00 in RDX is a parameter struct smi_info

crash> rd ffff8810588b5a00 20
ffff8810588b5a00:  ffff8810588b6000 0000000000000000   .`.X............
ffff8810588b5a10:  ffff880853264400 ffffffffa05417e0   .D&S......T.....
ffff8810588b5a20:  24a024a000000000 0000000000000000   .....$.$........
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a30:  0000000000000000 0000000000000000   ................
ffff8810588b5a40:  ffffffffa053a040 ffffffffa053a060   @.S.....`.S.....
ffff8810588b5a50:  0000000000000000 0000000100000001   ................
ffff8810588b5a60:  0000000000000000 0000000000000e00   ................
ffff8810588b5a70:  ffffffffa053a580 ffffffffa053a6e0   ..S.......S.....
ffff8810588b5a80:  ffffffffa053a4a0 ffffffffa053a250   ..S.....P.S.....
ffff8810588b5a90:  0000000500000002 0000000000000000   ................

Unfortunately the top of this area is already detroyed by someone.
But because of two reasonns we think this is struct smi_info
 1) The address included in between  ffff8810588b5a70 and ffff8810588b5a80:
  are inside of ipmi_si_intf.c  see crash> module ffff88085779d2c0

 2) We've found the area which point this.
  It is offset 0x68 of  ffff880859df4000

crash> rd  ffff880859df4000 100
ffff880859df4000:  0000000000000000 0000000000000001   ................
ffff880859df4010:  ffffffffa0535290 dead000000000200   .RS.............
ffff880859df4020:  ffff880859df4020 ffff880859df4020    @.Y.... @.Y....
ffff880859df4030:  0000000000000002 0000000000100010   ................
ffff880859df4040:  ffff880859df4040 ffff880859df4040   @@.Y....@@.Y....
ffff880859df4050:  0000000000000000 0000000000000000   ................
ffff880859df4060:  0000000000000000 ffff8810588b5a00   .........Z.X....
ffff880859df4070:  0000000000000001 ffff880859df4078   ........x@.Y....

 If we regards it as struct ipmi_smi in shutdown process
 it looks consistent.

The remedy for this apparent race is affixed below.

Signed-off-by: Tony Camuso <tcamuso@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This was first introduced in 7ea0ed2 ipmi: Make the
message handler easier to use for SMI interfaces
where some code was moved outside of the rcu_read_lock()
and the lock was not added.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
vchong pushed a commit that referenced this pull request Oct 4, 2018
[ 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>
vchong pushed a commit that referenced this pull request Oct 4, 2018
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>
vchong pushed a commit that referenced this pull request Oct 5, 2018
[ Upstream commit 934140a ]

cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview.  However, it has no ref on that monitor object or on the
associated operation.

What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object.  However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.

If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.

Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock.  The op can then be enqueued after the lock is
dropped.

The bug can manifest in one of a couple of ways.  The first manifestation
looks like:

 FS-Cache:
 FS-Cache: Assertion failed
 FS-Cache: 6 == 5 is false
 ------------[ cut here ]------------
 kernel BUG at fs/fscache/operation.c:494!
 RIP: 0010:fscache_put_operation+0x1e3/0x1f0
 ...
 fscache_op_work_func+0x26/0x50
 process_one_work+0x131/0x290
 worker_thread+0x45/0x360
 kthread+0xf8/0x130
 ? create_worker+0x190/0x190
 ? kthread_cancel_work_sync+0x10/0x10
 ret_from_fork+0x1f/0x30

This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().

The bug can also manifest like the following:

 kernel BUG at fs/fscache/operation.c:69!
 ...
    [exception RIP: fscache_enqueue_operation+246]
 ...
 #7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
 #8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
 #9 [ffff883fff083c48] __wake_up_common at ffffffff810af028

I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.

Fixes: 9ae326a ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: Lei Xue <carmark.dlut@gmail.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Reported-by: Anthony DeRobertis <aderobertis@metrics.net>
Reported-by: NeilBrown <neilb@suse.com>
Reported-by: Daniel Axtens <dja@axtens.net>
Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Oct 5, 2018
commit a5ba1d9 upstream.

We have reports of the following crash:

    PID: 7 TASK: ffff88085c6d61c0 CPU: 1 COMMAND: "kworker/u25:0"
    #0 [ffff88085c6db710] machine_kexec at ffffffff81046239
    #1 [ffff88085c6db760] crash_kexec at ffffffff810fc248
    #2 [ffff88085c6db830] oops_end at ffffffff81008ae7
    #3 [ffff88085c6db860] no_context at ffffffff81050b8f
    #4 [ffff88085c6db8b0] __bad_area_nosemaphore at ffffffff81050d75
    #5 [ffff88085c6db900] bad_area_nosemaphore at ffffffff81050e83
    #6 [ffff88085c6db910] __do_page_fault at ffffffff8105132e
    #7 [ffff88085c6db9b0] do_page_fault at ffffffff8105152c
    #8 [ffff88085c6db9c0] page_fault at ffffffff81a3f122
    [exception RIP: uart_put_char+149]
    RIP: ffffffff814b67b5 RSP: ffff88085c6dba78 RFLAGS: 00010006
    RAX: 0000000000000292 RBX: ffffffff827c5120 RCX: 0000000000000081
    RDX: 0000000000000000 RSI: 000000000000005f RDI: ffffffff827c5120
    RBP: ffff88085c6dba98 R8: 000000000000012c R9: ffffffff822ea320
    R10: ffff88085fe4db04 R11: 0000000000000001 R12: ffff881059f9c000
    R13: 0000000000000001 R14: 000000000000005f R15: 0000000000000fba
    ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
    #9 [ffff88085c6dbaa0] tty_put_char at ffffffff81497544
    #10 [ffff88085c6dbac0] do_output_char at ffffffff8149c91c
    #11 [ffff88085c6dbae0] __process_echoes at ffffffff8149cb8b
    #12 [ffff88085c6dbb30] commit_echoes at ffffffff8149cdc2
    #13 [ffff88085c6dbb60] n_tty_receive_buf_fast at ffffffff8149e49b
    #14 [ffff88085c6dbbc0] __receive_buf at ffffffff8149ef5a
    #15 [ffff88085c6dbc20] n_tty_receive_buf_common at ffffffff8149f016
    #16 [ffff88085c6dbca0] n_tty_receive_buf2 at ffffffff8149f194
    #17 [ffff88085c6dbcb0] flush_to_ldisc at ffffffff814a238a
    #18 [ffff88085c6dbd50] process_one_work at ffffffff81090be2
    #19 [ffff88085c6dbe20] worker_thread at ffffffff81091b4d
    #20 [ffff88085c6dbeb0] kthread at ffffffff81096384
    #21 [ffff88085c6dbf50] ret_from_fork at ffffffff81a3d69f​

after slogging through some dissasembly:

ffffffff814b6720 <uart_put_char>:
ffffffff814b6720:	55                   	push   %rbp
ffffffff814b6721:	48 89 e5             	mov    %rsp,%rbp
ffffffff814b6724:	48 83 ec 20          	sub    $0x20,%rsp
ffffffff814b6728:	48 89 1c 24          	mov    %rbx,(%rsp)
ffffffff814b672c:	4c 89 64 24 08       	mov    %r12,0x8(%rsp)
ffffffff814b6731:	4c 89 6c 24 10       	mov    %r13,0x10(%rsp)
ffffffff814b6736:	4c 89 74 24 18       	mov    %r14,0x18(%rsp)
ffffffff814b673b:	e8 b0 8e 58 00       	callq  ffffffff81a3f5f0 <mcount>
ffffffff814b6740:	4c 8b a7 88 02 00 00 	mov    0x288(%rdi),%r12
ffffffff814b6747:	45 31 ed             	xor    %r13d,%r13d
ffffffff814b674a:	41 89 f6             	mov    %esi,%r14d
ffffffff814b674d:	49 83 bc 24 70 01 00 	cmpq   $0x0,0x170(%r12)
ffffffff814b6754:	00 00
ffffffff814b6756:	49 8b 9c 24 80 01 00 	mov    0x180(%r12),%rbx
ffffffff814b675d:	00
ffffffff814b675e:	74 2f                	je     ffffffff814b678f <uart_put_char+0x6f>
ffffffff814b6760:	48 89 df             	mov    %rbx,%rdi
ffffffff814b6763:	e8 a8 67 58 00       	callq  ffffffff81a3cf10 <_raw_spin_lock_irqsave>
ffffffff814b6768:	41 8b 8c 24 78 01 00 	mov    0x178(%r12),%ecx
ffffffff814b676f:	00
ffffffff814b6770:	89 ca                	mov    %ecx,%edx
ffffffff814b6772:	f7 d2                	not    %edx
ffffffff814b6774:	41 03 94 24 7c 01 00 	add    0x17c(%r12),%edx
ffffffff814b677b:	00
ffffffff814b677c:	81 e2 ff 0f 00 00    	and    $0xfff,%edx
ffffffff814b6782:	75 23                	jne    ffffffff814b67a7 <uart_put_char+0x87>
ffffffff814b6784:	48 89 c6             	mov    %rax,%rsi
ffffffff814b6787:	48 89 df             	mov    %rbx,%rdi
ffffffff814b678a:	e8 e1 64 58 00       	callq  ffffffff81a3cc70 <_raw_spin_unlock_irqrestore>
ffffffff814b678f:	44 89 e8             	mov    %r13d,%eax
ffffffff814b6792:	48 8b 1c 24          	mov    (%rsp),%rbx
ffffffff814b6796:	4c 8b 64 24 08       	mov    0x8(%rsp),%r12
ffffffff814b679b:	4c 8b 6c 24 10       	mov    0x10(%rsp),%r13
ffffffff814b67a0:	4c 8b 74 24 18       	mov    0x18(%rsp),%r14
ffffffff814b67a5:	c9                   	leaveq
ffffffff814b67a6:	c3                   	retq
ffffffff814b67a7:	49 8b 94 24 70 01 00 	mov    0x170(%r12),%rdx
ffffffff814b67ae:	00
ffffffff814b67af:	48 63 c9             	movslq %ecx,%rcx
ffffffff814b67b2:	41 b5 01             	mov    $0x1,%r13b
ffffffff814b67b5:	44 88 34 0a          	mov    %r14b,(%rdx,%rcx,1)
ffffffff814b67b9:	41 8b 94 24 78 01 00 	mov    0x178(%r12),%edx
ffffffff814b67c0:	00
ffffffff814b67c1:	83 c2 01             	add    $0x1,%edx
ffffffff814b67c4:	81 e2 ff 0f 00 00    	and    $0xfff,%edx
ffffffff814b67ca:	41 89 94 24 78 01 00 	mov    %edx,0x178(%r12)
ffffffff814b67d1:	00
ffffffff814b67d2:	eb b0                	jmp    ffffffff814b6784 <uart_put_char+0x64>
ffffffff814b67d4:	66 66 66 2e 0f 1f 84 	data32 data32 nopw %cs:0x0(%rax,%rax,1)
ffffffff814b67db:	00 00 00 00 00

for our build, this is crashing at:

    circ->buf[circ->head] = c;

Looking in uart_port_startup(), it seems that circ->buf (state->xmit.buf)
protected by the "per-port mutex", which based on uart_port_check() is
state->port.mutex. Indeed, the lock acquired in uart_put_char() is
uport->lock, i.e. not the same lock.

Anyway, since the lock is not acquired, if uart_shutdown() is called, the
last chunk of that function may release state->xmit.buf before its assigned
to null, and cause the race above.

To fix it, let's lock uport->lock when allocating/deallocating
state->xmit.buf in addition to the per-port mutex.

v2: switch to locking uport->lock on allocation/deallocation instead of
    locking the per-port mutex in uart_put_char. Note that since
    uport->lock is a spin lock, we have to switch the allocation to
    GFP_ATOMIC.
v3: move the allocation outside the lock, so we can switch back to
    GFP_KERNEL

Signed-off-by: Tycho Andersen <tycho@tycho.ws>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Oct 5, 2018
commit 286e877 upstream.

Commit efda1b5 ("acpi, nfit, libnvdimm: fix / harden ars_status output length handling")
Introduced additional hardening for ambiguity in the ACPI spec for
ars_status output sizing. However, it had a couple of cases mixed up.
Where it should have been checking for (and returning) "out_field[1] -
4" it was using "out_field[1] - 8" and vice versa.

This caused a four byte discrepancy in the buffer size passed on to
the command handler, and in some cases, this caused memory corruption
like:

  ./daxdev-errors.sh: line 76: 24104 Aborted   (core dumped) ./daxdev-errors $busdev $region
  malloc(): memory corruption
  Program received signal SIGABRT, Aborted.
  [...]
  #5  0x00007ffff7865a2e in calloc () from /lib64/libc.so.6
  #6  0x00007ffff7bc2970 in ndctl_bus_cmd_new_ars_status (ars_cap=ars_cap@entry=0x6153b0) at ars.c:136
  #7  0x0000000000401644 in check_ars_status (check=0x7fffffffdeb0, bus=0x604c20) at daxdev-errors.c:144
  #8  test_daxdev_clear_error (region_name=<optimized out>, bus_name=<optimized out>)
      at daxdev-errors.c:332

Cc: <stable@vger.kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Lukasz Dorau <lukasz.dorau@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Fixes: efda1b5 ("acpi, nfit, libnvdimm: fix / harden ars_status output length handling")
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-of-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Oct 5, 2018
commit f52bb98 upstream.

Commit 6d526ee ("arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA")
only enabled HOLES_IN_ZONE for NUMA systems because the NUMA code was
choking on the missing zone for nomap pages. This problem doesn't just
apply to NUMA systems.

If the architecture doesn't set HAVE_ARCH_PFN_VALID, pfn_valid() will
return true if the pfn is part of a valid sparsemem section.

When working with multiple pages, the mm code uses pfn_valid_within()
to test each page it uses within the sparsemem section is valid. On
most systems memory comes in MAX_ORDER_NR_PAGES chunks which all
have valid/initialised struct pages. In this case pfn_valid_within()
is optimised out.

Systems where this isn't true (e.g. due to nomap) should set
HOLES_IN_ZONE and provide HAVE_ARCH_PFN_VALID so that mm tests each
page as it works with it.

Currently non-NUMA arm64 systems can't enable HOLES_IN_ZONE, leading to
a VM_BUG_ON():

| page:fffffdff802e1780 is uninitialized and poisoned
| raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
| raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff
| page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
| ------------[ cut here ]------------
| kernel BUG at include/linux/mm.h:978!
| Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[...]
| CPU: 1 PID: 25236 Comm: dd Not tainted 4.18.0 #7
| Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| pstate: 40000085 (nZcv daIf -PAN -UAO)
| pc : move_freepages_block+0x144/0x248
| lr : move_freepages_block+0x144/0x248
| sp : fffffe0071177680
[...]
| Process dd (pid: 25236, stack limit = 0x0000000094cc07fb)
| Call trace:
|  move_freepages_block+0x144/0x248
|  steal_suitable_fallback+0x100/0x16c
|  get_page_from_freelist+0x440/0xb20
|  __alloc_pages_nodemask+0xe8/0x838
|  new_slab+0xd4/0x418
|  ___slab_alloc.constprop.27+0x380/0x4a8
|  __slab_alloc.isra.21.constprop.26+0x24/0x34
|  kmem_cache_alloc+0xa8/0x180
|  alloc_buffer_head+0x1c/0x90
|  alloc_page_buffers+0x68/0xb0
|  create_empty_buffers+0x20/0x1ec
|  create_page_buffers+0xb0/0xf0
|  __block_write_begin_int+0xc4/0x564
|  __block_write_begin+0x10/0x18
|  block_write_begin+0x48/0xd0
|  blkdev_write_begin+0x28/0x30
|  generic_perform_write+0x98/0x16c
|  __generic_file_write_iter+0x138/0x168
|  blkdev_write_iter+0x80/0xf0
|  __vfs_write+0xe4/0x10c
|  vfs_write+0xb4/0x168
|  ksys_write+0x44/0x88
|  sys_write+0xc/0x14
|  el0_svc_naked+0x30/0x34
| Code: aa1303e0 90001a01 91296421 94008902 (d4210000)
| ---[ end trace 1601ba47f6e883fe ]---

Remove the NUMA dependency.

Link: https://www.spinics.net/lists/arm-kernel/msg671851.html
Cc: <stable@vger.kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Tested-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Oct 5, 2018
[ Upstream commit 78ee994 ]

Because rfi_flush_fallback runs immediately before the return to
userspace it currently runs with the user r1 (stack pointer). This
means if we oops in there we will report a bad kernel stack pointer in
the exception entry path, eg:

  Bad kernel stack pointer 7ffff7150e40 at c0000000000023b4
  Oops: Bad kernel stack pointer, sig: 6 [#1]
  LE SMP NR_CPUS=32 NUMA PowerNV
  Modules linked in:
  CPU: 0 PID: 1246 Comm: klogd Not tainted 4.18.0-rc2-gcc-7.3.1-00175-g0443f8a69ba3 #7
  NIP:  c0000000000023b4 LR: 0000000010053e00 CTR: 0000000000000040
  REGS: c0000000fffe7d40 TRAP: 4100   Not tainted  (4.18.0-rc2-gcc-7.3.1-00175-g0443f8a69ba3)
  MSR:  9000000002803031 <SF,HV,VEC,VSX,FP,ME,IR,DR,LE>  CR: 44000442  XER: 20000000
  CFAR: c00000000000bac8 IRQMASK: c0000000f1e66a80
  GPR00: 0000000002000000 00007ffff7150e40 00007fff93a99900 0000000000000020
  ...
  NIP [c0000000000023b4] rfi_flush_fallback+0x34/0x80
  LR [0000000010053e00] 0x10053e00

Although the NIP tells us where we were, and the TRAP number tells us
what happened, it would still be nicer if we could report the actual
exception rather than barfing about the stack pointer.

We an do that fairly simply by loading the kernel stack pointer on
entry and restoring the user value before returning. That way we see a
regular oops such as:

  Unrecoverable exception 4100 at c00000000000239c
  Oops: Unrecoverable exception, sig: 6 [#1]
  LE SMP NR_CPUS=32 NUMA PowerNV
  Modules linked in:
  CPU: 0 PID: 1251 Comm: klogd Not tainted 4.18.0-rc3-gcc-7.3.1-00097-g4ebfcac65acd-dirty #40
  NIP:  c00000000000239c LR: 0000000010053e00 CTR: 0000000000000040
  REGS: c0000000f1e17bb0 TRAP: 4100   Not tainted  (4.18.0-rc3-gcc-7.3.1-00097-g4ebfcac65acd-dirty)
  MSR:  9000000002803031 <SF,HV,VEC,VSX,FP,ME,IR,DR,LE>  CR: 44000442  XER: 20000000
  CFAR: c00000000000bac8 IRQMASK: 0
  ...
  NIP [c00000000000239c] rfi_flush_fallback+0x3c/0x80
  LR [0000000010053e00] 0x10053e00
  Call Trace:
  [c0000000f1e17e30] [c00000000000b9e4] system_call+0x5c/0x70 (unreliable)

Note this shouldn't make the kernel stack pointer vulnerable to a
meltdown attack, because it should be flushed from the cache before we
return to userspace. The user r1 value will be in the cache, because
we load it in the return path, but that is harmless.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vchong pushed a commit that referenced this pull request Oct 5, 2018
[ Upstream commit 46b3722 ]

We occasionaly hit following assert failure in 'perf top', when processing the
/proc info in multiple threads.

  perf: ...include/linux/refcount.h:109: refcount_inc:
        Assertion `!(!refcount_inc_not_zero(r))' failed.

The gdb backtrace looks like this:

  [Switching to Thread 0x7ffff11ba700 (LWP 13749)]
  0x00007ffff50839fb in raise () from /lib64/libc.so.6
  (gdb)
  #0  0x00007ffff50839fb in raise () from /lib64/libc.so.6
  #1  0x00007ffff5085800 in abort () from /lib64/libc.so.6
  #2  0x00007ffff507c0da in __assert_fail_base () from /lib64/libc.so.6
  #3  0x00007ffff507c152 in __assert_fail () from /lib64/libc.so.6
  #4  0x0000000000535373 in refcount_inc (r=0x7fffdc009be0)
      at ...include/linux/refcount.h:109
  #5  0x00000000005354f1 in comm_str__get (cs=0x7fffdc009bc0)
      at util/comm.c:24
  #6  0x00000000005356bd in __comm_str__findnew (str=0x7fffd000b260 ":2",
      root=0xbed5c0 <comm_str_root>) at util/comm.c:72
  #7  0x000000000053579e in comm_str__findnew (str=0x7fffd000b260 ":2",
      root=0xbed5c0 <comm_str_root>) at util/comm.c:95
  #8  0x000000000053582e in comm__new (str=0x7fffd000b260 ":2",
      timestamp=0, exec=false) at util/comm.c:111
  #9  0x00000000005363bc in thread__new (pid=2, tid=2) at util/thread.c:57
  #10 0x0000000000523da0 in ____machine__findnew_thread (machine=0xbfde38,
      threads=0xbfdf28, pid=2, tid=2, create=true) at util/machine.c:457
  #11 0x0000000000523eb4 in __machine__findnew_thread (machine=0xbfde38,
  ...

The failing assertion is this one:

  REFCOUNT_WARN(!refcount_inc_not_zero(r), ...

The problem is that we keep global comm_str_root list, which
is accessed by multiple threads during the 'perf top' startup
and following 2 paths can race:

  thread 1:
    ...
    thread__new
      comm__new
        comm_str__findnew
          down_write(&comm_str_lock);
          __comm_str__findnew
            comm_str__get

  thread 2:
    ...
    comm__override or comm__free
      comm_str__put
        refcount_dec_and_test
          down_write(&comm_str_lock);
          rb_erase(&cs->rb_node, &comm_str_root);

Because thread 2 first decrements the refcnt and only after then it removes the
struct comm_str from the list, the thread 1 can find this object on the list
with refcnt equls to 0 and hit the assert.

This patch fixes the thread 1 __comm_str__findnew path, by ignoring objects
that already dropped the refcnt to 0. For the rest of the objects we take the
refcnt before comparing its name and release it afterwards with comm_str__put,
which can also release the object completely.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20180720101740.GA27176@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jenswi-linaro pushed a commit to jenswi-linaro/linux-1 that referenced this pull request Sep 6, 2021
Commit b10d6bc ("arch, drivers: replace for_each_membock() with
for_each_mem_range()") didn't take into account that when there is
movable_node parameter in the kernel command line, for_each_mem_range()
would skip ranges marked with MEMBLOCK_HOTPLUG.

The page table setup code in POWER uses for_each_mem_range() to create
the linear mapping of the physical memory and since the regions marked
as MEMORY_HOTPLUG are skipped, they never make it to the linear map.

A later access to the memory in those ranges will fail:

  BUG: Unable to handle kernel data access on write at 0xc000000400000000
  Faulting instruction address: 0xc00000000008a3c0
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 0 PID: 53 Comm: kworker/u2:0 Not tainted 5.13.0 linaro-swg#7
  NIP:  c00000000008a3c0 LR: c0000000003c1ed8 CTR: 0000000000000040
  REGS: c000000008a57770 TRAP: 0300   Not tainted  (5.13.0)
  MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 84222202  XER: 20040000
  CFAR: c0000000003c1ed4 DAR: c000000400000000 DSISR: 42000000 IRQMASK: 0
  GPR00: c0000000003c1ed8 c000000008a57a10 c0000000019da700 c000000400000000
  GPR04: 0000000000000280 0000000000000180 0000000000000400 0000000000000200
  GPR08: 0000000000000100 0000000000000080 0000000000000040 0000000000000300
  GPR12: 0000000000000380 c000000001bc0000 c0000000001660c8 c000000006337e00
  GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
  GPR20: 0000000040000000 0000000020000000 c000000001a81990 c000000008c30000
  GPR24: c000000008c20000 c000000001a81998 000fffffffff0000 c000000001a819a0
  GPR28: c000000001a81908 c00c000001000000 c000000008c40000 c000000008a64680
  NIP clear_user_page+0x50/0x80
  LR __handle_mm_fault+0xc88/0x1910
  Call Trace:
    __handle_mm_fault+0xc44/0x1910 (unreliable)
    handle_mm_fault+0x130/0x2a0
    __get_user_pages+0x248/0x610
    __get_user_pages_remote+0x12c/0x3e0
    get_arg_page+0x54/0xf0
    copy_string_kernel+0x11c/0x210
    kernel_execve+0x16c/0x220
    call_usermodehelper_exec_async+0x1b0/0x2f0
    ret_from_kernel_thread+0x5c/0x70
  Instruction dump:
  79280fa4 79271764 79261f24 794ae8e2 7ca94214 7d683a14 7c893a14 7d893050
  7d4903a6 60000000 60000000 60000000 <7c001fec> 7c091fec 7c081fec 7c051fec
  ---[ end trace 490b8c67e6075e09 ]---

Making for_each_mem_range() include MEMBLOCK_HOTPLUG regions in the
traversal fixes this issue.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1976100
Link: https://lkml.kernel.org/r/20210712071132.20902-1-rppt@kernel.org
Fixes: b10d6bc ("arch, drivers: replace for_each_membock() with for_each_mem_range()")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>	[5.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
jenswi-linaro pushed a commit to jenswi-linaro/linux-1 that referenced this pull request Sep 6, 2021
…upt()

An interrupt handler shall not be called from another interrupt
handler otherwise this leads to problems like the following:

  Kernel attempted to write user page (afd4fa84) - exploit attempt? (uid: 1000)
  ------------[ cut here ]------------
  Bug: Write fault blocked by KUAP!
  WARNING: CPU: 0 PID: 1617 at arch/powerpc/mm/fault.c:230 do_page_fault+0x484/0x720
  Modules linked in:
  CPU: 0 PID: 1617 Comm: sshd Tainted: G        W         5.13.0-pmac-00010-g8393422eb77 linaro-swg#7
  NIP:  c001b77c LR: c001b77c CTR: 00000000
  REGS: cb9e5bc0 TRAP: 0700   Tainted: G        W          (5.13.0-pmac-00010-g8393422eb77)
  MSR:  00021032 <ME,IR,DR,RI>  CR: 24942424  XER: 00000000

  GPR00: c001b77c cb9e5c80 c1582c00 00000021 3ffffbff 085b0000 00000027 c8eb644c
  GPR08: 00000023 00000000 00000000 00000000 24942424 0063f8c8 00000000 000186a0
  GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90
  GPR24: 00000040 afd4fa96 00000040 02000000 c1fda6c0 afd4fa84 00000300 cb9e5cc0
  NIP [c001b77c] do_page_fault+0x484/0x720
  LR [c001b77c] do_page_fault+0x484/0x720
  Call Trace:
  [cb9e5c80] [c001b77c] do_page_fault+0x484/0x720 (unreliable)
  [cb9e5cb0] [c000424c] DataAccess_virt+0xd4/0xe4
  --- interrupt: 300 at __copy_tofrom_user+0x110/0x20c
  NIP:  c001f9b4 LR: c03250a0 CTR: 00000004
  REGS: cb9e5cc0 TRAP: 0300   Tainted: G        W          (5.13.0-pmac-00010-g8393422eb77)
  MSR:  00009032 <EE,ME,IR,DR,RI>  CR: 48028468  XER: 20000000
  DAR: afd4fa84 DSISR: 0a000000
  GPR00: 20726f6f cb9e5d80 c1582c00 00000004 cb9e5e3a 00000016 afd4fa80 00000000
  GPR08: 3835202d 72777872 2d78722d 00000004 28028464 0063f8c8 00000000 000186a0
  GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90
  GPR24: 00000040 afd4fa96 00000040 cb9e5e0c 00000daa a0000000 cb9e5e98 afd4fa56
  NIP [c001f9b4] __copy_tofrom_user+0x110/0x20c
  LR [c03250a0] _copy_to_iter+0x144/0x990
  --- interrupt: 300
  [cb9e5d80] [c03e89c0] n_tty_read+0xa4/0x598 (unreliable)
  [cb9e5df0] [c03e2a0c] tty_read+0xdc/0x2b4
  [cb9e5e80] [c0156bf8] vfs_read+0x274/0x340
  [cb9e5f00] [c01571ac] ksys_read+0x70/0x118
  [cb9e5f30] [c0016048] ret_from_syscall+0x0/0x28
  --- interrupt: c00 at 0xa7855c88
  NIP:  a7855c88 LR: a7855c5c CTR: 00000000
  REGS: cb9e5f40 TRAP: 0c00   Tainted: G        W          (5.13.0-pmac-00010-g8393422eb77)
  MSR:  0000d032 <EE,PR,ME,IR,DR,RI>  CR: 2402446c  XER: 00000000

  GPR00: 00000003 afd4ec70 a72137d0 0000000b afd4ecac 00004000 0065a990 00000800
  GPR08: 00000000 a7947930 00000000 00000004 c15831b0 0063f8c8 00000000 000186a0
  GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 0065a9e0 00000001 0065fac0
  GPR24: 00000000 00000089 00664050 00000000 00668e30 a720c8dc a7943ff4 0065f9b0
  NIP [a7855c88] 0xa7855c88
  LR [a7855c5c] 0xa7855c5c
  --- interrupt: c00
  Instruction dump:
  3884aa88 38630178 48076861 807f0080 48042e45 2f830000 419e0148 3c80c079
  3c60c076 38841be4 386301c0 4801f705 <0fe00000> 3860000b 4bfffe30 3c80c06b
  ---[ end trace fd69b91a8046c2e5 ]---

Here the problem is that by re-enterring an exception handler,
kuap_save_and_lock() is called a second time with this time KUAP
access locked, leading to regs->kuap being overwritten hence
KUAP not being unlocked at exception exit as expected.

Do not call do_IRQ() from timer_interrupt() directly. Instead,
redefine do_IRQ() as a standard function named __do_IRQ(), and
call it from both do_IRQ() and time_interrupt() handlers.

Fixes: 3a96570 ("powerpc: convert interrupt handlers to use wrappers")
Cc: stable@vger.kernel.org # v5.12+
Reported-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c17d234f4927d39a1d7100864a8e1145323d33a0.1628611927.git.christophe.leroy@csgroup.eu
odeprez pushed a commit to odeprez/linux-swg that referenced this pull request Oct 3, 2023
Fix an error detected by memory sanitizer:
```
==4033==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x55fb0fbedfc7 in read_alias_info tools/perf/util/pmu.c:457:6
    linaro-swg#1 0x55fb0fbea339 in check_info_data tools/perf/util/pmu.c:1434:2
    linaro-swg#2 0x55fb0fbea339 in perf_pmu__check_alias tools/perf/util/pmu.c:1504:9
    linaro-swg#3 0x55fb0fbdca85 in parse_events_add_pmu tools/perf/util/parse-events.c:1429:32
    linaro-swg#4 0x55fb0f965230 in parse_events_parse tools/perf/util/parse-events.y:299:6
    linaro-swg#5 0x55fb0fbdf6b2 in parse_events__scanner tools/perf/util/parse-events.c:1822:8
    linaro-swg#6 0x55fb0fbdf8c1 in __parse_events tools/perf/util/parse-events.c:2094:8
    linaro-swg#7 0x55fb0fa8ffa9 in parse_events tools/perf/util/parse-events.h:41:9
    linaro-swg#8 0x55fb0fa8ffa9 in test_event tools/perf/tests/parse-events.c:2393:8
    linaro-swg#9 0x55fb0fa8f458 in test__pmu_events tools/perf/tests/parse-events.c:2551:15
    linaro-swg#10 0x55fb0fa6d93f in run_test tools/perf/tests/builtin-test.c:242:9
    linaro-swg#11 0x55fb0fa6d93f in test_and_print tools/perf/tests/builtin-test.c:271:8
    linaro-swg#12 0x55fb0fa6d082 in __cmd_test tools/perf/tests/builtin-test.c:442:5
    linaro-swg#13 0x55fb0fa6d082 in cmd_test tools/perf/tests/builtin-test.c:564:9
    linaro-swg#14 0x55fb0f942720 in run_builtin tools/perf/perf.c:322:11
    linaro-swg#15 0x55fb0f942486 in handle_internal_command tools/perf/perf.c:375:8
    linaro-swg#16 0x55fb0f941dab in run_argv tools/perf/perf.c:419:2
    linaro-swg#17 0x55fb0f941dab in main tools/perf/perf.c:535:3
```

Fixes: 7b723db ("perf pmu: Be lazy about loading event info files from sysfs")
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20230914022425.1489035-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
odeprez pushed a commit to odeprez/linux-swg that referenced this pull request Oct 9, 2023
The following call trace shows a deadlock issue due to recursive locking of
mutex "device_mutex". First lock acquire is in target_for_each_device() and
second in target_free_device().

 PID: 148266   TASK: ffff8be21ffb5d00  CPU: 10   COMMAND: "iscsi_ttx"
  #0 [ffffa2bfc9ec3b18] __schedule at ffffffffa8060e7f
  linaro-swg#1 [ffffa2bfc9ec3ba0] schedule at ffffffffa8061224
  linaro-swg#2 [ffffa2bfc9ec3bb8] schedule_preempt_disabled at ffffffffa80615ee
  linaro-swg#3 [ffffa2bfc9ec3bc8] __mutex_lock at ffffffffa8062fd7
  linaro-swg#4 [ffffa2bfc9ec3c40] __mutex_lock_slowpath at ffffffffa80631d3
  linaro-swg#5 [ffffa2bfc9ec3c50] mutex_lock at ffffffffa806320c
  linaro-swg#6 [ffffa2bfc9ec3c68] target_free_device at ffffffffc0935998 [target_core_mod]
  linaro-swg#7 [ffffa2bfc9ec3c90] target_core_dev_release at ffffffffc092f975 [target_core_mod]
  linaro-swg#8 [ffffa2bfc9ec3ca0] config_item_put at ffffffffa79d250f
  linaro-swg#9 [ffffa2bfc9ec3cd0] config_item_put at ffffffffa79d2583
 linaro-swg#10 [ffffa2bfc9ec3ce0] target_devices_idr_iter at ffffffffc0933f3a [target_core_mod]
 linaro-swg#11 [ffffa2bfc9ec3d00] idr_for_each at ffffffffa803f6fc
 linaro-swg#12 [ffffa2bfc9ec3d60] target_for_each_device at ffffffffc0935670 [target_core_mod]
 linaro-swg#13 [ffffa2bfc9ec3d98] transport_deregister_session at ffffffffc0946408 [target_core_mod]
 linaro-swg#14 [ffffa2bfc9ec3dc8] iscsit_close_session at ffffffffc09a44a6 [iscsi_target_mod]
 linaro-swg#15 [ffffa2bfc9ec3df0] iscsit_close_connection at ffffffffc09a4a88 [iscsi_target_mod]
 linaro-swg#16 [ffffa2bfc9ec3df8] finish_task_switch at ffffffffa76e5d07
 linaro-swg#17 [ffffa2bfc9ec3e78] iscsit_take_action_for_connection_exit at ffffffffc0991c23 [iscsi_target_mod]
 linaro-swg#18 [ffffa2bfc9ec3ea0] iscsi_target_tx_thread at ffffffffc09a403b [iscsi_target_mod]
 linaro-swg#19 [ffffa2bfc9ec3f08] kthread at ffffffffa76d8080
 linaro-swg#20 [ffffa2bfc9ec3f50] ret_from_fork at ffffffffa8200364

Fixes: 36d4cb4 ("scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion")
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Link: https://lore.kernel.org/r/20230918225848.66463-1-junxiao.bi@oracle.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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