RFE: always return a value from the netport/netnode/netif caches #3

stephensmalley · 2016-11-17T15:44:39Z

Currently under memory pressure the netport/netnode/netif caches can fail to return a SID to the caller, thereby causing an operation to fail. However, the cache can always return the value obtained from the security server, even if it cannot allocate a cache node to save it for future lookups (just as the AVC does). Fix the caches to do so.

[ 3843.132217] WARNING: CPU: 20 PID: 1227 at kernel/softirq.c:150 __local_bh_enable_ip+0x6b/0x90 [ 3843.142815] Modules linked in: ... [ 3843.294328] CPU: 20 PID: 1227 Comm: kworker/20:1H Tainted: G E 4.8.0-rc1+ #3 [ 3843.304944] Hardware name: Dell Inc. PowerEdge R720/0X6H47, BIOS 1.4.8 10/25/2012 [ 3843.314798] Workqueue: kblockd blk_timeout_work [ 3843.321350] 0000000000000086 00000000a32f4533 ffff8802216d7bd8 ffffffff8135c3cf [ 3843.331146] 0000000000000000 0000000000000000 ffff8802216d7c18 ffffffff8108d661 [ 3843.340918] 00000096216d7c50 0000000000000200 ffff8802d07cc828 ffff8801b3632550 [ 3843.350687] Call Trace: [ 3843.354866] [<ffffffff8135c3cf>] dump_stack+0x63/0x84 [ 3843.362061] [<ffffffff8108d661>] __warn+0xd1/0xf0 [ 3843.368851] [<ffffffff8108d79d>] warn_slowpath_null+0x1d/0x20 [ 3843.376791] [<ffffffff810930eb>] __local_bh_enable_ip+0x6b/0x90 [ 3843.384903] [<ffffffff816fe7be>] _raw_spin_unlock_bh+0x1e/0x20 [ 3843.392940] [<ffffffffa085f710>] beiscsi_alloc_pdu+0x2f0/0x6e0 [be2iscsi] [ 3843.402076] [<ffffffffa06bc358>] __iscsi_conn_send_pdu+0xf8/0x370 [libiscsi] [ 3843.411549] [<ffffffffa06bc6fe>] iscsi_send_nopout+0xbe/0x110 [libiscsi] [ 3843.420639] [<ffffffffa06bd98b>] iscsi_eh_cmd_timed_out+0x29b/0x2b0 [libiscsi] [ 3843.430339] [<ffffffff814cd1de>] scsi_times_out+0x5e/0x250 [ 3843.438119] [<ffffffff813374af>] blk_rq_timed_out+0x1f/0x60 [ 3843.446009] [<ffffffff8133759d>] blk_timeout_work+0xad/0x150 [ 3843.454010] [<ffffffff810a6642>] process_one_work+0x152/0x400 [ 3843.462114] [<ffffffff810a6f35>] worker_thread+0x125/0x4b0 [ 3843.469961] [<ffffffff810a6e10>] ? rescuer_thread+0x380/0x380 [ 3843.478116] [<ffffffff810aca28>] kthread+0xd8/0xf0 [ 3843.485212] [<ffffffff816fedff>] ret_from_fork+0x1f/0x40 [ 3843.492908] [<ffffffff810ac950>] ? kthread_park+0x60/0x60 [ 3843.500715] ---[ end trace 57ec0a1d8f0dd3a0 ]--- [ 3852.328667] NMI watchdog: Watchdog detected hard LOCKUP on cpu 1Kernel panic - not syncing: Hard LOCKUP blk_timeout_work takes queue_lock spin_lock with interrupts disabled before invoking iscsi_eh_cmd_timed_out. This causes a WARN_ON_ONCE in spin_unlock_bh for wrb_lock/io_sgl_lock/mgmt_sgl_lock. CPU was kept busy in lot of bottom half work with interrupts disabled thus causing hard lock up. Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Chris Leech <cleech@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

We shouldn't free cert->pub->key in x509_cert_parse() because x509_free_certificate() also does this: BUG: Double free or freeing an invalid pointer ... Call Trace: [<ffffffff81896c20>] dump_stack+0x63/0x83 [<ffffffff81356571>] kasan_object_err+0x21/0x70 [<ffffffff81356ed9>] kasan_report_double_free+0x49/0x60 [<ffffffff813561ad>] kasan_slab_free+0x9d/0xc0 [<ffffffff81350b7a>] kfree+0x8a/0x1a0 [<ffffffff81844fbf>] public_key_free+0x1f/0x30 [<ffffffff818455d4>] x509_free_certificate+0x24/0x90 [<ffffffff818460bc>] x509_cert_parse+0x2bc/0x300 [<ffffffff81846cae>] x509_key_preparse+0x3e/0x330 [<ffffffff818444cf>] asymmetric_key_preparse+0x6f/0x100 [<ffffffff8178bec0>] key_create_or_update+0x260/0x5f0 [<ffffffff8178e6d9>] SyS_add_key+0x199/0x2a0 [<ffffffff821d823b>] entry_SYSCALL_64_fastpath+0x1e/0xad Object at ffff880110bd1900, in cache kmalloc-512 size: 512 .... Freed: PID = 2579 [<ffffffff8104283b>] save_stack_trace+0x1b/0x20 [<ffffffff813558f6>] save_stack+0x46/0xd0 [<ffffffff81356183>] kasan_slab_free+0x73/0xc0 [<ffffffff81350b7a>] kfree+0x8a/0x1a0 [<ffffffff818460a3>] x509_cert_parse+0x2a3/0x300 [<ffffffff81846cae>] x509_key_preparse+0x3e/0x330 [<ffffffff818444cf>] asymmetric_key_preparse+0x6f/0x100 [<ffffffff8178bec0>] key_create_or_update+0x260/0x5f0 [<ffffffff8178e6d9>] SyS_add_key+0x199/0x2a0 [<ffffffff821d823b>] entry_SYSCALL_64_fastpath+0x1e/0xad Fixes: db6c43b ("crypto: KEYS: convert public key and digsig asym to the akcipher api") Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <james.l.morris@oracle.com>

This fixes CVE-2016-8650. If mpi_powm() is given a zero exponent, it wants to immediately return either 1 or 0, depending on the modulus. However, if the result was initalised with zero limb space, no limbs space is allocated and a NULL-pointer exception ensues. Fix this by allocating a minimal amount of limb space for the result when the 0-exponent case when the result is 1 and not touching the limb space when the result is 0. This affects the use of RSA keys and X.509 certificates that carry them. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 PGD 0 Oops: 0002 [#1] SMP Modules linked in: CPU: 3 PID: 3014 Comm: keyctl Not tainted 4.9.0-rc6-fscache+ #278 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 task: ffff8804011944c0 task.stack: ffff880401294000 RIP: 0010:[<ffffffff8138ce5d>] [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 RSP: 0018:ffff880401297ad8 EFLAGS: 00010212 RAX: 0000000000000000 RBX: ffff88040868bec0 RCX: ffff88040868bba0 RDX: ffff88040868b260 RSI: ffff88040868bec0 RDI: ffff88040868bee0 RBP: ffff880401297ba8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000047 R11: ffffffff8183b210 R12: 0000000000000000 R13: ffff8804087c7600 R14: 000000000000001f R15: ffff880401297c50 FS: 00007f7a7918c700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000401250000 CR4: 00000000001406e0 Stack: ffff88040868bec0 0000000000000020 ffff880401297b00 ffffffff81376cd4 0000000000000100 ffff880401297b10 ffffffff81376d12 ffff880401297b30 ffffffff81376f37 0000000000000100 0000000000000000 ffff880401297ba8 Call Trace: [<ffffffff81376cd4>] ? __sg_page_iter_next+0x43/0x66 [<ffffffff81376d12>] ? sg_miter_get_next_page+0x1b/0x5d [<ffffffff81376f37>] ? sg_miter_next+0x17/0xbd [<ffffffff8138ba3a>] ? mpi_read_raw_from_sgl+0xf2/0x146 [<ffffffff8132a95c>] rsa_verify+0x9d/0xee [<ffffffff8132acca>] ? pkcs1pad_sg_set_buf+0x2e/0xbb [<ffffffff8132af40>] pkcs1pad_verify+0xc0/0xe1 [<ffffffff8133cb5e>] public_key_verify_signature+0x1b0/0x228 [<ffffffff8133d974>] x509_check_for_self_signed+0xa1/0xc4 [<ffffffff8133cdde>] x509_cert_parse+0x167/0x1a1 [<ffffffff8133d609>] x509_key_preparse+0x21/0x1a1 [<ffffffff8133c3d7>] asymmetric_key_preparse+0x34/0x61 [<ffffffff812fc9f3>] key_create_or_update+0x145/0x399 [<ffffffff812fe227>] SyS_add_key+0x154/0x19e [<ffffffff81001c2b>] do_syscall_64+0x80/0x191 [<ffffffff816825e4>] entry_SYSCALL64_slow_path+0x25/0x25 Code: 56 41 55 41 54 53 48 81 ec a8 00 00 00 44 8b 71 04 8b 42 04 4c 8b 67 18 45 85 f6 89 45 80 0f 84 b4 06 00 00 85 c0 75 2f 41 ff ce <49> c7 04 24 01 00 00 00 b0 01 75 0b 48 8b 41 18 48 83 38 01 0f RIP [<ffffffff8138ce5d>] mpi_powm+0x32/0x7e6 RSP <ffff880401297ad8> CR2: 0000000000000000 ---[ end trace d82015255d4a5d8d ]--- Basically, this is a backport of a libgcrypt patch: http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=patch;h=6e1adb05d290aeeb1c230c763970695f4a538526 Fixes: cdec9cb ("crypto: GnuPG based MPI lib - source files (part 1)") Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com> cc: linux-ima-devel@lists.sourceforge.net cc: stable@vger.kernel.org Signed-off-by: James Morris <james.l.morris@oracle.com>

…/git/jmorris/linux-security Pull keys fixes from James Morris: "From David: - Fix mpi_powm()'s handling of a number with a zero exponent [CVE-2016-8650]. Integrate my and Andrey's patches for mpi_powm() and use mpi_resize() instead of RESIZE_IF_NEEDED() - the latter adds a duplicate check into the execution path of a trivial case we don't normally expect to be taken. - Fix double free in X.509 error handling" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: mpi: Fix NULL ptr dereference in mpi_powm() [ver #3] X.509: Fix double free in x509_cert_parse() [ver #3]

Guillaume Nault says: ==================== l2tp: fixes for l2tp_ip and l2tp_ip6 socket handling This series addresses problems found while working on commit 32c2311 ("l2tp: fix racy SOCK_ZAPPED flag check in l2tp_ip{,6}_bind()"). The first three patches fix races in socket's connect, recv and bind operations. The last two ones fix scenarios where l2tp fails to correctly lookup its userspace sockets. Apart from the last patch, which is l2tp_ip6 specific, every patch fixes the same problem in the L2TP IPv4 and IPv6 code. All problems fixed by this series exist since the creation of the l2tp_ip and l2tp_ip6 modules. Changes since v1: * Patch #3: fix possible uninitialised use of 'ret' in l2tp_ip_bind(). ==================== Acked-by: James Chapman <jchapman@katalix.com>

Since commit: 4bcc595 ("printk: reinstate KERN_CONT for printing continuation lines") printk() requires KERN_CONT to continue log messages. Lots of printk() in lockdep.c and print_ip_sym() don't have it. As the result lockdep reports are completely messed up. Add missing KERN_CONT and inline print_ip_sym() where necessary. Example of a messed up report: 0-rc5+ #41 Not tainted ------------------------------------------------------- syz-executor0/5036 is trying to acquire lock: ( rtnl_mutex ){+.+.+.} , at: [<ffffffff86b3d6ac>] rtnl_lock+0x1c/0x20 but task is already holding lock: ( &net->packet.sklist_lock ){+.+...} , at: [<ffffffff873541a6>] packet_diag_dump+0x1a6/0x1920 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ( &net->packet.sklist_lock +.+...} ... Without this patch all scripts that parse kernel bug reports are broken. Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: andreyknvl@google.com Cc: aryabinin@virtuozzo.com Cc: joe@perches.com Cc: syzkaller@googlegroups.com Link: http://lkml.kernel.org/r/1480343083-48731-1-git-send-email-dvyukov@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>

Hayes Wang says: ==================== r8152: fix scheduling napi v3: simply the argument for patch #3. Replace &tp->napi with napi. v2: Add smp_mb__after_atomic() for patch #1. v1: Scheduling the napi during the following periods would let it be ignored. And the events wouldn't be handled until next napi_schedule() is called. 1. after napi_disable and before napi_enable(). 2. after all actions of napi function is completed and before calling napi_complete(). If no next napi_schedule() is called, tx or rx would stop working. In order to avoid these situations, the followings solutions are applied. 1. prevent start_xmit() from calling napi_schedule() during runtime suspend or after napi_disable(). 2. re-schedule the napi for tx if it is necessary. 3. check if any rx is finished or not after napi_enable(). ==================== Signed-off-by: David S. Miller <davem@davemloft.net>

This patch reverts commit f80de88 and avoids that sending a WRITE SAME command to the iSCSI initiator triggers the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000014 TARGET_CORE[iSCSI]: Expected Transfer Length: 260096 does not match SCSI CDB Length: 512 for SAM Opcode: 0x41 IP: iscsi_tcp_segment_done+0x20b/0x310 [libiscsi_tcp] Oops: 0000 [#1] SMP Modules linked in: target_core_user uio target_core_iblock target_core_file iscsi_target_mod target_core_mod netconsole configfs crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 crypto_simd cryptd glue_helper virtio_console virtio_rng virtio_balloon serio_raw i2c_piix4 acpi_cpufreq button iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ext4 jbd2 mbcache virtio_blk virtio_net psmouse floppy drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm virtio_pci CPU: 2 PID: 5 Comm: kworker/u8:0 Not tainted 4.10.0-rc5-debug+ #3 Workqueue: iscsi_q_0 iscsi_xmitworker [libiscsi] RIP: 0010:iscsi_tcp_segment_done+0x20b/0x310 [libiscsi_tcp] Call Trace: iscsi_sw_tcp_xmit_segment+0x84/0x120 [iscsi_tcp] iscsi_sw_tcp_pdu_xmit+0x51/0x180 [iscsi_tcp] iscsi_tcp_task_xmit+0xb3/0x290 [libiscsi_tcp] iscsi_xmit_task+0x4e/0xc0 [libiscsi] iscsi_xmitworker+0x243/0x330 [libiscsi] process_one_work+0x1d8/0x4b0 worker_thread+0x49/0x4a0 kthread+0x102/0x140 Fixes: f80de88 ("sd: remove __data_len hack for WRITE SAME") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Jens Axboe <axboe@fb.com> Cc: Lee Duncan <lduncan@suse.com> Cc: Chris Leech <cleech@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@fb.com>

The Amlogic Meson GXBB/GXL/GXM secure monitor uses part of the memory space, this patch adds these reserved zones. Without such reserved memory zones, running the following stress command : $ stress-ng --vm 16 --vm-bytes 128M --timeout 10s multiple times: Could lead to the following kernel crashes : [ 46.937975] Bad mode in Error handler detected on CPU1, code 0xbf000000 -- SError ... [ 47.058536] Internal error: Attempting to execute userspace memory: 8600000f [#3] PREEMPT SMP ... Instead of the OOM killer. Fixes: 4f24eda ("ARM64: dts: Prepare configs for Amlogic Meson GXBaby") Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Reviewed-by: Andreas Färber <afaerber@suse.de> [khilman: added Fixes tag, added _reserved and unit addresses] Signed-off-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

When we look for microcode blobs, we first try builtin and if that doesn't succeed, we fallback to the initrd supplied to the kernel. However, at some point doing boot, that initrd gets jettisoned and we shouldn't access it anymore. But we do, as the below KASAN report shows. That's because find_microcode_in_initrd() doesn't check whether the initrd is still valid or not. So do that. ================================================================== BUG: KASAN: use-after-free in find_cpio_data Read of size 1 by task swapper/1/0 page:ffffea0000db9d40 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x100000000000000() raw: 0100000000000000 0000000000000000 0000000000000001 00000000ffffffff raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.10.0-rc5-debug-00075-g2dbde22 #3 Hardware name: Dell Inc. XPS 13 9360/0839Y6, BIOS 1.2.3 12/01/2016 Call Trace: dump_stack ? _atomic_dec_and_lock ? __dump_page kasan_report_error ? pointer ? find_cpio_data __asan_report_load1_noabort ? find_cpio_data find_cpio_data ? vsprintf ? dump_stack ? get_ucode_user ? print_usage_bug find_microcode_in_initrd __load_ucode_intel ? collect_cpu_info_early ? debug_check_no_locks_freed load_ucode_intel_ap ? collect_cpu_info ? trace_hardirqs_on ? flat_send_IPI_mask_allbutself load_ucode_ap ? get_builtin_firmware ? flush_tlb_func ? do_raw_spin_trylock ? cpumask_weight cpu_init ? trace_hardirqs_off ? play_dead_common ? native_play_dead ? hlt_play_dead ? syscall_init ? arch_cpu_idle_dead ? do_idle start_secondary start_cpu Memory state around the buggy address: ffff880036e74f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff880036e74f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff880036e75000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff880036e75080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff880036e75100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Tested-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170126165833.evjemhbqzaepirxo@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>

Olof reported that on a machine which has a BIOS wreckaged TSC the timestamps in dmesg are making a large jump because the TSC value is jumping forward after resetting the TSC ADJUST register to a sane value. This can be avoided by calling the TSC ADJUST saniziting function before initializing the per cpu sched clock machinery. That takes the offset into account and avoid the time jump. What cannot be avoided is that the 'Firmware Bug' warnings on the secondary CPUs are printed with the large time offsets because it would be too much effort and ugly hackery to print those warnings into a buffer and emit them after the adjustemt on the starting CPUs. It's a firmware bug and should be fixed in firmware. The weird timestamps are collateral damage and just illustrate the sillyness of the BIOS folks: [ 0.397445] smp: Bringing up secondary CPUs ... [ 0.402100] x86: Booting SMP configuration: [ 0.406343] .... node #0, CPUs: #1 [1265776479.930667] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU1: -2978888639183101 [1265776479.944664] TSC ADJUST synchronize: Reference CPU0: 0 CPU1: -2978888639183101 [ 0.508119] #2 [1265776480.032346] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU2: -2978888639183677 [1265776480.044192] TSC ADJUST synchronize: Reference CPU0: 0 CPU2: -2978888639183677 [ 0.607643] #3 [1265776480.131874] [Firmware Bug]: TSC ADJUST differs: Reference CPU0: -2978888639075328 CPU3: -2978888639184530 [1265776480.143720] TSC ADJUST synchronize: Reference CPU0: 0 CPU3: -2978888639184530 [ 0.707108] smp: Brought up 1 node, 4 CPUs [ 0.711271] smpboot: Total of 4 processors activated (21698.88 BogoMIPS) Reported-by: Olof Johansson <olof@lixom.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20170209151231.411460506@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

We cannot do printk() from tk_debug_account_sleep_time(), because tk_debug_account_sleep_time() is called under tk_core seq lock. The reason why printk() is unsafe there is that console_sem may invoke scheduler (up()->wake_up_process()->activate_task()), which, in turn, can return back to timekeeping code, for instance, via get_time()->ktime_get(), deadlocking the system on tk_core seq lock. [ 48.950592] ====================================================== [ 48.950622] [ INFO: possible circular locking dependency detected ] [ 48.950622] 4.10.0-rc7-next-20170213+ #101 Not tainted [ 48.950622] ------------------------------------------------------- [ 48.950622] kworker/0:0/3 is trying to acquire lock: [ 48.950653] (tk_core){----..}, at: [<c01cc624>] retrigger_next_event+0x4c/0x90 [ 48.950683] but task is already holding lock: [ 48.950683] (hrtimer_bases.lock){-.-...}, at: [<c01cc610>] retrigger_next_event+0x38/0x90 [ 48.950714] which lock already depends on the new lock. [ 48.950714] the existing dependency chain (in reverse order) is: [ 48.950714] -> #5 (hrtimer_bases.lock){-.-...}: [ 48.950744] _raw_spin_lock_irqsave+0x50/0x64 [ 48.950775] lock_hrtimer_base+0x28/0x58 [ 48.950775] hrtimer_start_range_ns+0x20/0x5c8 [ 48.950775] __enqueue_rt_entity+0x320/0x360 [ 48.950805] enqueue_rt_entity+0x2c/0x44 [ 48.950805] enqueue_task_rt+0x24/0x94 [ 48.950836] ttwu_do_activate+0x54/0xc0 [ 48.950836] try_to_wake_up+0x248/0x5c8 [ 48.950836] __setup_irq+0x420/0x5f0 [ 48.950836] request_threaded_irq+0xdc/0x184 [ 48.950866] devm_request_threaded_irq+0x58/0xa4 [ 48.950866] omap_i2c_probe+0x530/0x6a0 [ 48.950897] platform_drv_probe+0x50/0xb0 [ 48.950897] driver_probe_device+0x1f8/0x2cc [ 48.950897] __driver_attach+0xc0/0xc4 [ 48.950927] bus_for_each_dev+0x6c/0xa0 [ 48.950927] bus_add_driver+0x100/0x210 [ 48.950927] driver_register+0x78/0xf4 [ 48.950958] do_one_initcall+0x3c/0x16c [ 48.950958] kernel_init_freeable+0x20c/0x2d8 [ 48.950958] kernel_init+0x8/0x110 [ 48.950988] ret_from_fork+0x14/0x24 [ 48.950988] -> #4 (&rt_b->rt_runtime_lock){-.-...}: [ 48.951019] _raw_spin_lock+0x40/0x50 [ 48.951019] rq_offline_rt+0x9c/0x2bc [ 48.951019] set_rq_offline.part.2+0x2c/0x58 [ 48.951049] rq_attach_root+0x134/0x144 [ 48.951049] cpu_attach_domain+0x18c/0x6f4 [ 48.951049] build_sched_domains+0xba4/0xd80 [ 48.951080] sched_init_smp+0x68/0x10c [ 48.951080] kernel_init_freeable+0x160/0x2d8 [ 48.951080] kernel_init+0x8/0x110 [ 48.951080] ret_from_fork+0x14/0x24 [ 48.951110] -> #3 (&rq->lock){-.-.-.}: [ 48.951110] _raw_spin_lock+0x40/0x50 [ 48.951141] task_fork_fair+0x30/0x124 [ 48.951141] sched_fork+0x194/0x2e0 [ 48.951141] copy_process.part.5+0x448/0x1a20 [ 48.951171] _do_fork+0x98/0x7e8 [ 48.951171] kernel_thread+0x2c/0x34 [ 48.951171] rest_init+0x1c/0x18c [ 48.951202] start_kernel+0x35c/0x3d4 [ 48.951202] 0x8000807c [ 48.951202] -> #2 (&p->pi_lock){-.-.-.}: [ 48.951232] _raw_spin_lock_irqsave+0x50/0x64 [ 48.951232] try_to_wake_up+0x30/0x5c8 [ 48.951232] up+0x4c/0x60 [ 48.951263] __up_console_sem+0x2c/0x58 [ 48.951263] console_unlock+0x3b4/0x650 [ 48.951263] vprintk_emit+0x270/0x474 [ 48.951293] vprintk_default+0x20/0x28 [ 48.951293] printk+0x20/0x30 [ 48.951324] kauditd_hold_skb+0x94/0xb8 [ 48.951324] kauditd_thread+0x1a4/0x56c [ 48.951324] kthread+0x104/0x148 [ 48.951354] ret_from_fork+0x14/0x24 [ 48.951354] -> #1 ((console_sem).lock){-.....}: [ 48.951385] _raw_spin_lock_irqsave+0x50/0x64 [ 48.951385] down_trylock+0xc/0x2c [ 48.951385] __down_trylock_console_sem+0x24/0x80 [ 48.951385] console_trylock+0x10/0x8c [ 48.951416] vprintk_emit+0x264/0x474 [ 48.951416] vprintk_default+0x20/0x28 [ 48.951416] printk+0x20/0x30 [ 48.951446] tk_debug_account_sleep_time+0x5c/0x70 [ 48.951446] __timekeeping_inject_sleeptime.constprop.3+0x170/0x1a0 [ 48.951446] timekeeping_resume+0x218/0x23c [ 48.951477] syscore_resume+0x94/0x42c [ 48.951477] suspend_enter+0x554/0x9b4 [ 48.951477] suspend_devices_and_enter+0xd8/0x4b4 [ 48.951507] enter_state+0x934/0xbd4 [ 48.951507] pm_suspend+0x14/0x70 [ 48.951507] state_store+0x68/0xc8 [ 48.951538] kernfs_fop_write+0xf4/0x1f8 [ 48.951538] __vfs_write+0x1c/0x114 [ 48.951538] vfs_write+0xa0/0x168 [ 48.951568] SyS_write+0x3c/0x90 [ 48.951568] __sys_trace_return+0x0/0x10 [ 48.951568] -> #0 (tk_core){----..}: [ 48.951599] lock_acquire+0xe0/0x294 [ 48.951599] ktime_get_update_offsets_now+0x5c/0x1d4 [ 48.951629] retrigger_next_event+0x4c/0x90 [ 48.951629] on_each_cpu+0x40/0x7c [ 48.951629] clock_was_set_work+0x14/0x20 [ 48.951660] process_one_work+0x2b4/0x808 [ 48.951660] worker_thread+0x3c/0x550 [ 48.951660] kthread+0x104/0x148 [ 48.951690] ret_from_fork+0x14/0x24 [ 48.951690] other info that might help us debug this: [ 48.951690] Chain exists of: tk_core --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock [ 48.951721] Possible unsafe locking scenario: [ 48.951721] CPU0 CPU1 [ 48.951721] ---- ---- [ 48.951721] lock(hrtimer_bases.lock); [ 48.951751] lock(&rt_b->rt_runtime_lock); [ 48.951751] lock(hrtimer_bases.lock); [ 48.951751] lock(tk_core); [ 48.951782] *** DEADLOCK *** [ 48.951782] 3 locks held by kworker/0:0/3: [ 48.951782] #0: ("events"){.+.+.+}, at: [<c0156590>] process_one_work+0x1f8/0x808 [ 48.951812] #1: (hrtimer_work){+.+...}, at: [<c0156590>] process_one_work+0x1f8/0x808 [ 48.951843] #2: (hrtimer_bases.lock){-.-...}, at: [<c01cc610>] retrigger_next_event+0x38/0x90 [ 48.951843] stack backtrace: [ 48.951873] CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.10.0-rc7-next-20170213+ [ 48.951904] Workqueue: events clock_was_set_work [ 48.951904] [<c0110208>] (unwind_backtrace) from [<c010c224>] (show_stack+0x10/0x14) [ 48.951934] [<c010c224>] (show_stack) from [<c04ca6c0>] (dump_stack+0xac/0xe0) [ 48.951934] [<c04ca6c0>] (dump_stack) from [<c019b5cc>] (print_circular_bug+0x1d0/0x308) [ 48.951965] [<c019b5cc>] (print_circular_bug) from [<c019d2a8>] (validate_chain+0xf50/0x1324) [ 48.951965] [<c019d2a8>] (validate_chain) from [<c019ec18>] (__lock_acquire+0x468/0x7e8) [ 48.951995] [<c019ec18>] (__lock_acquire) from [<c019f634>] (lock_acquire+0xe0/0x294) [ 48.951995] [<c019f634>] (lock_acquire) from [<c01d0ea0>] (ktime_get_update_offsets_now+0x5c/0x1d4) [ 48.952026] [<c01d0ea0>] (ktime_get_update_offsets_now) from [<c01cc624>] (retrigger_next_event+0x4c/0x90) [ 48.952026] [<c01cc624>] (retrigger_next_event) from [<c01e4e24>] (on_each_cpu+0x40/0x7c) [ 48.952056] [<c01e4e24>] (on_each_cpu) from [<c01cafc4>] (clock_was_set_work+0x14/0x20) [ 48.952056] [<c01cafc4>] (clock_was_set_work) from [<c015664c>] (process_one_work+0x2b4/0x808) [ 48.952087] [<c015664c>] (process_one_work) from [<c0157774>] (worker_thread+0x3c/0x550) [ 48.952087] [<c0157774>] (worker_thread) from [<c015d644>] (kthread+0x104/0x148) [ 48.952087] [<c015d644>] (kthread) from [<c0107830>] (ret_from_fork+0x14/0x24) Replace printk() with printk_deferred(), which does not call into the scheduler. Fixes: 0bf43f1 ("timekeeping: Prints the amounts of time spent during suspend") Reported-and-tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: John Stultz <john.stultz@linaro.org> Cc: "[4.9+]" <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20170215044332.30449-1-sergey.senozhatsky@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Commit 6664498 ("packet: call fanout_release, while UNREGISTERING a netdev"), unfortunately, introduced the following issues. 1. calling mutex_lock(&fanout_mutex) (fanout_release()) from inside rcu_read-side critical section. rcu_read_lock disables preemption, most often, which prohibits calling sleeping functions. [ ] include/linux/rcupdate.h:560 Illegal context switch in RCU read-side critical section! [ ] [ ] rcu_scheduler_active = 1, debug_locks = 0 [ ] 4 locks held by ovs-vswitchd/1969: [ ] #0: (cb_lock){++++++}, at: [<ffffffff8158a6c9>] genl_rcv+0x19/0x40 [ ] #1: (ovs_mutex){+.+.+.}, at: [<ffffffffa04878ca>] ovs_vport_cmd_del+0x4a/0x100 [openvswitch] [ ] #2: (rtnl_mutex){+.+.+.}, at: [<ffffffff81564157>] rtnl_lock+0x17/0x20 [ ] #3: (rcu_read_lock){......}, at: [<ffffffff81614165>] packet_notifier+0x5/0x3f0 [ ] [ ] Call Trace: [ ] [<ffffffff813770c1>] dump_stack+0x85/0xc4 [ ] [<ffffffff810c9077>] lockdep_rcu_suspicious+0x107/0x110 [ ] [<ffffffff810a2da7>] ___might_sleep+0x57/0x210 [ ] [<ffffffff810a2fd0>] __might_sleep+0x70/0x90 [ ] [<ffffffff8162e80c>] mutex_lock_nested+0x3c/0x3a0 [ ] [<ffffffff810de93f>] ? vprintk_default+0x1f/0x30 [ ] [<ffffffff81186e88>] ? printk+0x4d/0x4f [ ] [<ffffffff816106dd>] fanout_release+0x1d/0xe0 [ ] [<ffffffff81614459>] packet_notifier+0x2f9/0x3f0 2. calling mutex_lock(&fanout_mutex) inside spin_lock(&po->bind_lock). "sleeping function called from invalid context" [ ] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620 [ ] in_atomic(): 1, irqs_disabled(): 0, pid: 1969, name: ovs-vswitchd [ ] INFO: lockdep is turned off. [ ] Call Trace: [ ] [<ffffffff813770c1>] dump_stack+0x85/0xc4 [ ] [<ffffffff810a2f52>] ___might_sleep+0x202/0x210 [ ] [<ffffffff810a2fd0>] __might_sleep+0x70/0x90 [ ] [<ffffffff8162e80c>] mutex_lock_nested+0x3c/0x3a0 [ ] [<ffffffff816106dd>] fanout_release+0x1d/0xe0 [ ] [<ffffffff81614459>] packet_notifier+0x2f9/0x3f0 3. calling dev_remove_pack(&fanout->prot_hook), from inside spin_lock(&po->bind_lock) or rcu_read-side critical-section. dev_remove_pack() -> synchronize_net(), which might sleep. [ ] BUG: scheduling while atomic: ovs-vswitchd/1969/0x00000002 [ ] INFO: lockdep is turned off. [ ] Call Trace: [ ] [<ffffffff813770c1>] dump_stack+0x85/0xc4 [ ] [<ffffffff81186274>] __schedule_bug+0x64/0x73 [ ] [<ffffffff8162b8cb>] __schedule+0x6b/0xd10 [ ] [<ffffffff8162c5db>] schedule+0x6b/0x80 [ ] [<ffffffff81630b1d>] schedule_timeout+0x38d/0x410 [ ] [<ffffffff810ea3fd>] synchronize_sched_expedited+0x53d/0x810 [ ] [<ffffffff810ea6de>] synchronize_rcu_expedited+0xe/0x10 [ ] [<ffffffff8154eab5>] synchronize_net+0x35/0x50 [ ] [<ffffffff8154eae3>] dev_remove_pack+0x13/0x20 [ ] [<ffffffff8161077e>] fanout_release+0xbe/0xe0 [ ] [<ffffffff81614459>] packet_notifier+0x2f9/0x3f0 4. fanout_release() races with calls from different CPU. To fix the above problems, remove the call to fanout_release() under rcu_read_lock(). Instead, call __dev_remove_pack(&fanout->prot_hook) and netdev_run_todo will be happy that &dev->ptype_specific list is empty. In order to achieve this, I moved dev_{add,remove}_pack() out of fanout_{add,release} to __fanout_{link,unlink}. So, call to {,__}unregister_prot_hook() will make sure fanout->prot_hook is removed as well. Fixes: 6664498 ("packet: call fanout_release, while UNREGISTERING a netdev") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Anoob Soman <anoob.soman@citrix.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>

This is a story about 4 distinct (and very old) btrfs bugs. Commit c8b9781 ("Btrfs: Add zlib compression support") added three data corruption bugs for inline extents (bugs #1-3). Commit 93c82d5 ("Btrfs: zero page past end of inline file items") fixed bug #1: uncompressed inline extents followed by a hole and more extents could get non-zero data in the hole as they were read. The fix was to add a memset in btrfs_get_extent to zero out the hole. Commit 166ae5a ("btrfs: fix inline compressed read err corruption") fixed bug #2: compressed inline extents which contained non-zero bytes might be replaced with zero bytes in some cases. This patch removed an unhelpful memset from uncompress_inline, but the case where memset is required was missed. There is also a memset in the decompression code, but this only covers decompressed data that is shorter than the ram_bytes from the extent ref record. This memset doesn't cover the region between the end of the decompressed data and the end of the page. It has also moved around a few times over the years, so there's no single patch to refer to. This patch fixes bug #3: compressed inline extents followed by a hole and more extents could get non-zero data in the hole as they were read (i.e. bug #3 is the same as bug #1, but s/uncompressed/compressed/). The fix is the same: zero out the hole in the compressed case too, by putting a memset back in uncompress_inline, but this time with correct parameters. The last and oldest bug, bug #0, is the cause of the offending inline extent/hole/extent pattern. Bug #0 is a subtle and mostly-harmless quirk of behavior somewhere in the btrfs write code. In a few special cases, an inline extent and hole are allowed to persist where they normally would be combined with later extents in the file. A fast reproducer for bug #0 is presented below. A few offending extents are also created in the wild during large rsync transfers with the -S flag. A Linux kernel build (git checkout; make allyesconfig; make -j8) will produce a handful of offending files as well. Once an offending file is created, it can present different content to userspace each time it is read. Bug #0 is at least 4 and possibly 8 years old. I verified every vX.Y kernel back to v3.5 has this behavior. There are fossil records of this bug's effects in commits all the way back to v2.6.32. I have no reason to believe bug #0 wasn't present at the beginning of btrfs compression support in v2.6.29, but I can't easily test kernels that old to be sure. It is not clear whether bug #0 is worth fixing. A fix would likely require injecting extra reads into currently write-only paths, and most of the exceptional cases caused by bug #0 are already handled now. Whether we like them or not, bug #0's inline extents followed by holes are part of the btrfs de-facto disk format now, and we need to be able to read them without data corruption or an infoleak. So enough about bug #0, let's get back to bug #3 (this patch). An example of on-disk structure leading to data corruption found in the wild: item 61 key (606890 INODE_ITEM 0) itemoff 9662 itemsize 160 inode generation 50 transid 50 size 47424 nbytes 49141 block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0 flags 0x0(none) item 62 key (606890 INODE_REF 603050) itemoff 9642 itemsize 20 inode ref index 3 namelen 10 name: DB_File.so item 63 key (606890 EXTENT_DATA 0) itemoff 8280 itemsize 1362 inline extent data size 1341 ram 4085 compress(zlib) item 64 key (606890 EXTENT_DATA 4096) itemoff 8227 itemsize 53 extent data disk byte 5367308288 nr 20480 extent data offset 0 nr 45056 ram 45056 extent compression(zlib) Different data appears in userspace during each read of the 11 bytes between 4085 and 4096. The extent in item 63 is not long enough to fill the first page of the file, so a memset is required to fill the space between item 63 (ending at 4085) and item 64 (beginning at 4096) with zero. Here is a reproducer from Liu Bo, which demonstrates another method of creating the same inline extent and hole pattern: Using 'page_poison=on' kernel command line (or enable CONFIG_PAGE_POISONING) run the following: # touch foo # chattr +c foo # xfs_io -f -c "pwrite -W 0 1000" foo # xfs_io -f -c "falloc 4 8188" foo # od -x foo # echo 3 >/proc/sys/vm/drop_caches # od -x foo This produce the following on my box: Correct output: file contains 1000 data bytes followed by zeros: 0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd * 0001740 cdcd cdcd cdcd cdcd 0000 0000 0000 0000 0001760 0000 0000 0000 0000 0000 0000 0000 0000 * 0020000 Actual output: the data after the first 1000 bytes will be different each run: 0000000 cdcd cdcd cdcd cdcd cdcd cdcd cdcd cdcd * 0001740 cdcd cdcd cdcd cdcd 6c63 7400 635f 006d 0001760 5f74 6f43 7400 435f 0053 5f74 7363 7400 0002000 435f 0056 5f74 6164 7400 645f 0062 5f74 (...) Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: Chris Mason <clm@fb.com> Signed-off-by: Chris Mason <clm@fb.com>

The rcu_barrier() takes the cpu_hotplug mutex which itself is not reclaim-safe, and so rcu_barrier() is illegal from inside the shrinker. [ 309.661373] ========================================================= [ 309.661376] [ INFO: possible irq lock inversion dependency detected ] [ 309.661380] 4.11.0-rc1-CI-CI_DRM_2333+ #1 Tainted: G W [ 309.661383] --------------------------------------------------------- [ 309.661386] gem_exec_gttfil/6435 just changed the state of lock: [ 309.661389] (rcu_preempt_state.barrier_mutex){+.+.-.}, at: [<ffffffff81100731>] _rcu_barrier+0x31/0x160 [ 309.661399] but this lock took another, RECLAIM_FS-unsafe lock in the past: [ 309.661402] (cpu_hotplug.lock){+.+.+.} [ 309.661404] and interrupts could create inverse lock ordering between them. [ 309.661410] other info that might help us debug this: [ 309.661414] Possible interrupt unsafe locking scenario: [ 309.661417] CPU0 CPU1 [ 309.661419] ---- ---- [ 309.661421] lock(cpu_hotplug.lock); [ 309.661425] local_irq_disable(); [ 309.661432] lock(rcu_preempt_state.barrier_mutex); [ 309.661441] lock(cpu_hotplug.lock); [ 309.661446] <Interrupt> [ 309.661448] lock(rcu_preempt_state.barrier_mutex); [ 309.661453] *** DEADLOCK *** [ 309.661460] 4 locks held by gem_exec_gttfil/6435: [ 309.661464] #0: (sb_writers#10){.+.+.+}, at: [<ffffffff8120d83d>] vfs_write+0x17d/0x1f0 [ 309.661475] #1: (debugfs_srcu){......}, at: [<ffffffff81320491>] debugfs_use_file_start+0x41/0xa0 [ 309.661486] #2: (&attr->mutex){+.+.+.}, at: [<ffffffff8123a3e7>] simple_attr_write+0x37/0xe0 [ 309.661495] #3: (&dev->struct_mutex){+.+.+.}, at: [<ffffffffa0091b4a>] i915_drop_caches_set+0x3a/0x150 [i915] [ 309.661540] the shortest dependencies between 2nd lock and 1st lock: [ 309.661547] -> (cpu_hotplug.lock){+.+.+.} ops: 829 { [ 309.661553] HARDIRQ-ON-W at: [ 309.661560] __lock_acquire+0x5e5/0x1b50 [ 309.661565] lock_acquire+0xc9/0x220 [ 309.661572] __mutex_lock+0x6e/0x990 [ 309.661576] mutex_lock_nested+0x16/0x20 [ 309.661583] get_online_cpus+0x61/0x80 [ 309.661590] kmem_cache_create+0x25/0x1d0 [ 309.661596] debug_objects_mem_init+0x30/0x249 [ 309.661602] start_kernel+0x341/0x3fe [ 309.661607] x86_64_start_reservations+0x2a/0x2c [ 309.661612] x86_64_start_kernel+0x173/0x186 [ 309.661619] verify_cpu+0x0/0xfc [ 309.661622] SOFTIRQ-ON-W at: [ 309.661627] __lock_acquire+0x611/0x1b50 [ 309.661632] lock_acquire+0xc9/0x220 [ 309.661636] __mutex_lock+0x6e/0x990 [ 309.661641] mutex_lock_nested+0x16/0x20 [ 309.661646] get_online_cpus+0x61/0x80 [ 309.661650] kmem_cache_create+0x25/0x1d0 [ 309.661655] debug_objects_mem_init+0x30/0x249 [ 309.661660] start_kernel+0x341/0x3fe [ 309.661664] x86_64_start_reservations+0x2a/0x2c [ 309.661669] x86_64_start_kernel+0x173/0x186 [ 309.661674] verify_cpu+0x0/0xfc [ 309.661677] RECLAIM_FS-ON-W at: [ 309.661682] mark_held_locks+0x6f/0xa0 [ 309.661687] lockdep_trace_alloc+0xb3/0x100 [ 309.661693] kmem_cache_alloc_trace+0x31/0x2e0 [ 309.661699] __smpboot_create_thread.part.1+0x27/0xe0 [ 309.661704] smpboot_create_threads+0x61/0x90 [ 309.661709] cpuhp_invoke_callback+0x9c/0x8a0 [ 309.661713] cpuhp_up_callbacks+0x31/0xb0 [ 309.661718] _cpu_up+0x7a/0xc0 [ 309.661723] do_cpu_up+0x5f/0x80 [ 309.661727] cpu_up+0xe/0x10 [ 309.661734] smp_init+0x71/0xb3 [ 309.661738] kernel_init_freeable+0x94/0x19e [ 309.661743] kernel_init+0x9/0xf0 [ 309.661748] ret_from_fork+0x2e/0x40 [ 309.661752] INITIAL USE at: [ 309.661757] __lock_acquire+0x234/0x1b50 [ 309.661761] lock_acquire+0xc9/0x220 [ 309.661766] __mutex_lock+0x6e/0x990 [ 309.661771] mutex_lock_nested+0x16/0x20 [ 309.661775] get_online_cpus+0x61/0x80 [ 309.661780] __cpuhp_setup_state+0x44/0x170 [ 309.661785] page_alloc_init+0x23/0x3a [ 309.661790] start_kernel+0x124/0x3fe [ 309.661794] x86_64_start_reservations+0x2a/0x2c [ 309.661799] x86_64_start_kernel+0x173/0x186 [ 309.661804] verify_cpu+0x0/0xfc [ 309.661807] } [ 309.661813] ... key at: [<ffffffff81e37690>] cpu_hotplug+0xb0/0x100 [ 309.661817] ... acquired at: [ 309.661821] lock_acquire+0xc9/0x220 [ 309.661825] __mutex_lock+0x6e/0x990 [ 309.661829] mutex_lock_nested+0x16/0x20 [ 309.661833] get_online_cpus+0x61/0x80 [ 309.661837] _rcu_barrier+0x9f/0x160 [ 309.661841] rcu_barrier+0x10/0x20 [ 309.661847] netdev_run_todo+0x5f/0x310 [ 309.661852] rtnl_unlock+0x9/0x10 [ 309.661856] default_device_exit_batch+0x133/0x150 [ 309.661862] ops_exit_list.isra.0+0x4d/0x60 [ 309.661866] cleanup_net+0x1d8/0x2c0 [ 309.661872] process_one_work+0x1f4/0x6d0 [ 309.661876] worker_thread+0x49/0x4a0 [ 309.661881] kthread+0x107/0x140 [ 309.661884] ret_from_fork+0x2e/0x40 [ 309.661890] -> (rcu_preempt_state.barrier_mutex){+.+.-.} ops: 179 { [ 309.661896] HARDIRQ-ON-W at: [ 309.661901] __lock_acquire+0x5e5/0x1b50 [ 309.661905] lock_acquire+0xc9/0x220 [ 309.661910] __mutex_lock+0x6e/0x990 [ 309.661914] mutex_lock_nested+0x16/0x20 [ 309.661919] _rcu_barrier+0x31/0x160 [ 309.661923] rcu_barrier+0x10/0x20 [ 309.661928] netdev_run_todo+0x5f/0x310 [ 309.661932] rtnl_unlock+0x9/0x10 [ 309.661936] default_device_exit_batch+0x133/0x150 [ 309.661941] ops_exit_list.isra.0+0x4d/0x60 [ 309.661946] cleanup_net+0x1d8/0x2c0 [ 309.661951] process_one_work+0x1f4/0x6d0 [ 309.661955] worker_thread+0x49/0x4a0 [ 309.661960] kthread+0x107/0x140 [ 309.661964] ret_from_fork+0x2e/0x40 [ 309.661968] SOFTIRQ-ON-W at: [ 309.661972] __lock_acquire+0x611/0x1b50 [ 309.661977] lock_acquire+0xc9/0x220 [ 309.661981] __mutex_lock+0x6e/0x990 [ 309.661986] mutex_lock_nested+0x16/0x20 [ 309.661990] _rcu_barrier+0x31/0x160 [ 309.661995] rcu_barrier+0x10/0x20 [ 309.661999] netdev_run_todo+0x5f/0x310 [ 309.662003] rtnl_unlock+0x9/0x10 [ 309.662008] default_device_exit_batch+0x133/0x150 [ 309.662013] ops_exit_list.isra.0+0x4d/0x60 [ 309.662017] cleanup_net+0x1d8/0x2c0 [ 309.662022] process_one_work+0x1f4/0x6d0 [ 309.662027] worker_thread+0x49/0x4a0 [ 309.662031] kthread+0x107/0x140 [ 309.662035] ret_from_fork+0x2e/0x40 [ 309.662039] IN-RECLAIM_FS-W at: [ 309.662043] __lock_acquire+0x638/0x1b50 [ 309.662048] lock_acquire+0xc9/0x220 [ 309.662053] __mutex_lock+0x6e/0x990 [ 309.662058] mutex_lock_nested+0x16/0x20 [ 309.662062] _rcu_barrier+0x31/0x160 [ 309.662067] rcu_barrier+0x10/0x20 [ 309.662089] i915_gem_shrink_all+0x33/0x40 [i915] [ 309.662109] i915_drop_caches_set+0x141/0x150 [i915] [ 309.662114] simple_attr_write+0xc7/0xe0 [ 309.662119] full_proxy_write+0x4f/0x70 [ 309.662124] __vfs_write+0x23/0x120 [ 309.662128] vfs_write+0xc6/0x1f0 [ 309.662133] SyS_write+0x44/0xb0 [ 309.662138] entry_SYSCALL_64_fastpath+0x1c/0xb1 [ 309.662142] INITIAL USE at: [ 309.662147] __lock_acquire+0x234/0x1b50 [ 309.662151] lock_acquire+0xc9/0x220 [ 309.662156] __mutex_lock+0x6e/0x990 [ 309.662160] mutex_lock_nested+0x16/0x20 [ 309.662165] _rcu_barrier+0x31/0x160 [ 309.662169] rcu_barrier+0x10/0x20 [ 309.662174] netdev_run_todo+0x5f/0x310 [ 309.662178] rtnl_unlock+0x9/0x10 [ 309.662183] default_device_exit_batch+0x133/0x150 [ 309.662188] ops_exit_list.isra.0+0x4d/0x60 [ 309.662192] cleanup_net+0x1d8/0x2c0 [ 309.662197] process_one_work+0x1f4/0x6d0 [ 309.662202] worker_thread+0x49/0x4a0 [ 309.662206] kthread+0x107/0x140 [ 309.662210] ret_from_fork+0x2e/0x40 [ 309.662214] } [ 309.662220] ... key at: [<ffffffff81e4e1c8>] rcu_preempt_state+0x508/0x780 [ 309.662225] ... acquired at: [ 309.662229] check_usage_forwards+0x12b/0x130 [ 309.662233] mark_lock+0x360/0x6f0 [ 309.662237] __lock_acquire+0x638/0x1b50 [ 309.662241] lock_acquire+0xc9/0x220 [ 309.662245] __mutex_lock+0x6e/0x990 [ 309.662249] mutex_lock_nested+0x16/0x20 [ 309.662253] _rcu_barrier+0x31/0x160 [ 309.662257] rcu_barrier+0x10/0x20 [ 309.662279] i915_gem_shrink_all+0x33/0x40 [i915] [ 309.662298] i915_drop_caches_set+0x141/0x150 [i915] [ 309.662303] simple_attr_write+0xc7/0xe0 [ 309.662307] full_proxy_write+0x4f/0x70 [ 309.662311] __vfs_write+0x23/0x120 [ 309.662315] vfs_write+0xc6/0x1f0 [ 309.662319] SyS_write+0x44/0xb0 [ 309.662323] entry_SYSCALL_64_fastpath+0x1c/0xb1 [ 309.662329] stack backtrace: [ 309.662335] CPU: 1 PID: 6435 Comm: gem_exec_gttfil Tainted: G W 4.11.0-rc1-CI-CI_DRM_2333+ #1 [ 309.662342] Hardware name: Hewlett-Packard HP Compaq 8100 Elite SFF PC/304Ah, BIOS 786H1 v01.13 07/14/2011 [ 309.662348] Call Trace: [ 309.662354] dump_stack+0x67/0x92 [ 309.662359] print_irq_inversion_bug.part.19+0x1a4/0x1b0 [ 309.662365] check_usage_forwards+0x12b/0x130 [ 309.662369] mark_lock+0x360/0x6f0 [ 309.662374] ? print_shortest_lock_dependencies+0x1a0/0x1a0 [ 309.662379] __lock_acquire+0x638/0x1b50 [ 309.662383] ? __mutex_unlock_slowpath+0x3e/0x2e0 [ 309.662388] ? trace_hardirqs_on+0xd/0x10 [ 309.662392] ? _rcu_barrier+0x31/0x160 [ 309.662396] lock_acquire+0xc9/0x220 [ 309.662400] ? _rcu_barrier+0x31/0x160 [ 309.662404] ? _rcu_barrier+0x31/0x160 [ 309.662409] __mutex_lock+0x6e/0x990 [ 309.662412] ? _rcu_barrier+0x31/0x160 [ 309.662416] ? _rcu_barrier+0x31/0x160 [ 309.662421] ? synchronize_rcu_expedited+0x35/0xb0 [ 309.662426] ? _raw_spin_unlock_irqrestore+0x52/0x60 [ 309.662434] mutex_lock_nested+0x16/0x20 [ 309.662438] _rcu_barrier+0x31/0x160 [ 309.662442] rcu_barrier+0x10/0x20 [ 309.662464] i915_gem_shrink_all+0x33/0x40 [i915] [ 309.662484] i915_drop_caches_set+0x141/0x150 [i915] [ 309.662489] simple_attr_write+0xc7/0xe0 [ 309.662494] full_proxy_write+0x4f/0x70 [ 309.662498] __vfs_write+0x23/0x120 [ 309.662503] ? rcu_read_lock_sched_held+0x75/0x80 [ 309.662507] ? rcu_sync_lockdep_assert+0x2a/0x50 [ 309.662512] ? __sb_start_write+0x102/0x210 [ 309.662516] ? vfs_write+0x17d/0x1f0 [ 309.662520] vfs_write+0xc6/0x1f0 [ 309.662524] ? trace_hardirqs_on_caller+0xe7/0x200 [ 309.662529] SyS_write+0x44/0xb0 [ 309.662533] entry_SYSCALL_64_fastpath+0x1c/0xb1 [ 309.662537] RIP: 0033:0x7f507eac24a0 [ 309.662541] RSP: 002b:00007fffda8720e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 309.662548] RAX: ffffffffffffffda RBX: ffffffff81482bd3 RCX: 00007f507eac24a0 [ 309.662552] RDX: 0000000000000005 RSI: 00007fffda8720f0 RDI: 0000000000000005 [ 309.662557] RBP: ffffc9000048bf88 R08: 0000000000000000 R09: 000000000000002c [ 309.662561] R10: 0000000000000014 R11: 0000000000000246 R12: 00007fffda872230 [ 309.662566] R13: 00007fffda872228 R14: 0000000000000201 R15: 00007fffda8720f0 [ 309.662572] ? __this_cpu_preempt_check+0x13/0x20 Fixes: 0eafec6 ("drm/i915: Enable lockless lookup of request tracking via RCU") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100192 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: <stable@vger.kernel.org> # v4.9+ Link: http://patchwork.freedesktop.org/patch/msgid/20170314115019.18127-1-chris@chris-wilson.co.uk Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (cherry picked from commit bd784b7) Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170321144531.12344-1-chris@chris-wilson.co.uk

Dmitry reported a lockdep splat [1] (false positive) that we can fix by releasing the spinlock before calling icmp_send() from ip_expire() This is a false positive because sending an ICMP message can not possibly re-enter the IP frag engine. [1] [ INFO: possible circular locking dependency detected ] 4.10.0+ #29 Not tainted ------------------------------------------------------- modprobe/12392 is trying to acquire lock: (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] spin_lock include/linux/spinlock.h:299 [inline] (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] __netif_tx_lock include/linux/netdevice.h:3486 [inline] (_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 but task is already holding lock: (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock include/linux/spinlock.h:299 [inline] (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(&q->lock)->rlock){+.-...}: validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] ip_defrag+0x3a2/0x4130 net/ipv4/ip_fragment.c:669 ip_check_defrag+0x4e3/0x8b0 net/ipv4/ip_fragment.c:713 packet_rcv_fanout+0x282/0x800 net/packet/af_packet.c:1459 deliver_skb net/core/dev.c:1834 [inline] dev_queue_xmit_nit+0x294/0xa90 net/core/dev.c:1890 xmit_one net/core/dev.c:2903 [inline] dev_hard_start_xmit+0x16b/0xab0 net/core/dev.c:2923 sch_direct_xmit+0x31f/0x6d0 net/sched/sch_generic.c:182 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_resolve_output+0x6b9/0xb10 net/core/neighbour.c:1308 neigh_output include/net/neighbour.h:478 [inline] ip_finish_output2+0x8b8/0x15a0 net/ipv4/ip_output.c:228 ip_do_fragment+0x1d93/0x2720 net/ipv4/ip_output.c:672 ip_fragment.constprop.54+0x145/0x200 net/ipv4/ip_output.c:545 ip_finish_output+0x82d/0xe10 net/ipv4/ip_output.c:314 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 raw_sendmsg+0x26de/0x3a00 net/ipv4/raw.c:655 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 ___sys_sendmsg+0x4a3/0x9f0 net/socket.c:1985 __sys_sendmmsg+0x25c/0x750 net/socket.c:2075 SYSC_sendmmsg net/socket.c:2106 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2101 do_syscall_64+0x2e8/0x930 arch/x86/entry/common.c:281 return_from_SYSCALL_64+0x0/0x7a -> #0 (_xmit_ETHER#2){+.-...}: check_prev_add kernel/locking/lockdep.c:1830 [inline] check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940 validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] __netif_tx_lock include/linux/netdevice.h:3486 [inline] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_hh_output include/net/neighbour.h:468 [inline] neigh_output include/net/neighbour.h:476 [inline] ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268 expire_timers kernel/time/timer.c:1307 [inline] __run_timers+0x960/0xcf0 kernel/time/timer.c:1601 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:657 [inline] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707 __read_once_size include/linux/compiler.h:254 [inline] atomic_read arch/x86/include/asm/atomic.h:26 [inline] rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline] __rcu_is_watching kernel/rcu/tree.c:1133 [inline] rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147 rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline] filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335 do_fault_around mm/memory.c:3231 [inline] do_read_fault mm/memory.c:3265 [inline] do_fault+0xbd5/0x2080 mm/memory.c:3370 handle_pte_fault mm/memory.c:3600 [inline] __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&q->lock)->rlock); lock(_xmit_ETHER#2); lock(&(&q->lock)->rlock); lock(_xmit_ETHER#2); *** DEADLOCK *** 10 locks held by modprobe/12392: #0: (&mm->mmap_sem){++++++}, at: [<ffffffff81329758>] __do_page_fault+0x2b8/0xb60 arch/x86/mm/fault.c:1336 #1: (rcu_read_lock){......}, at: [<ffffffff8188cab6>] filemap_map_pages+0x1e6/0x1570 mm/filemap.c:2324 #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>] spin_lock include/linux/spinlock.h:299 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>] pte_alloc_one_map mm/memory.c:2944 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>] alloc_set_pte+0x13b8/0x1b90 mm/memory.c:3072 #3: (((&q->timer))){+.-...}, at: [<ffffffff81627e72>] lockdep_copy_map include/linux/lockdep.h:175 [inline] #3: (((&q->timer))){+.-...}, at: [<ffffffff81627e72>] call_timer_fn+0x1c2/0x820 kernel/time/timer.c:1258 #4: (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock include/linux/spinlock.h:299 [inline] #4: (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201 #5: (rcu_read_lock){......}, at: [<ffffffff8389a633>] ip_expire+0x1b3/0x6c0 net/ipv4/ip_fragment.c:216 #6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] spin_trylock include/linux/spinlock.h:309 [inline] #6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] icmp_xmit_lock net/ipv4/icmp.c:219 [inline] #6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] icmp_send+0x803/0x1c80 net/ipv4/icmp.c:681 #7: (rcu_read_lock_bh){......}, at: [<ffffffff838ab9a1>] ip_finish_output2+0x2c1/0x15a0 net/ipv4/ip_output.c:198 #8: (rcu_read_lock_bh){......}, at: [<ffffffff836d1dee>] __dev_queue_xmit+0x23e/0x1e60 net/core/dev.c:3324 #9: (dev->qdisc_running_key ?: &qdisc_running_key){+.....}, at: [<ffffffff836d3a27>] dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 stack backtrace: CPU: 0 PID: 12392 Comm: modprobe Not tainted 4.10.0+ #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:52 print_circular_bug+0x307/0x3b0 kernel/locking/lockdep.c:1204 check_prev_add kernel/locking/lockdep.c:1830 [inline] check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940 validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] __netif_tx_lock include/linux/netdevice.h:3486 [inline] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_hh_output include/net/neighbour.h:468 [inline] neigh_output include/net/neighbour.h:476 [inline] ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268 expire_timers kernel/time/timer.c:1307 [inline] __run_timers+0x960/0xcf0 kernel/time/timer.c:1601 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:657 [inline] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707 RIP: 0010:__read_once_size include/linux/compiler.h:254 [inline] RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline] RIP: 0010:__rcu_is_watching kernel/rcu/tree.c:1133 [inline] RIP: 0010:rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147 RSP: 0000:ffff8801c391f120 EFLAGS: 00000a03 ORIG_RAX: ffffffffffffff10 RAX: dffffc0000000000 RBX: ffff8801c391f148 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000055edd4374000 RDI: ffff8801dbe1ae0c RBP: ffff8801c391f1a0 R08: 0000000000000002 R09: 0000000000000000 R10: dffffc0000000000 R11: 0000000000000002 R12: 1ffff10038723e25 R13: ffff8801dbe1ae00 R14: ffff8801c391f680 R15: dffffc0000000000 </IRQ> rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline] filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335 do_fault_around mm/memory.c:3231 [inline] do_read_fault mm/memory.c:3265 [inline] do_fault+0xbd5/0x2080 mm/memory.c:3370 handle_pte_fault mm/memory.c:3600 [inline] __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011 RIP: 0033:0x7f83172f2786 RSP: 002b:00007fffe859ae80 EFLAGS: 00010293 RAX: 000055edd4373040 RBX: 00007f83175111c8 RCX: 000055edd4373238 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f8317510970 RBP: 00007fffe859afd0 R08: 0000000000000009 R09: 0000000000000000 R10: 0000000000000064 R11: 0000000000000000 R12: 000055edd4373040 R13: 0000000000000000 R14: 00007fffe859afe8 R15: 0000000000000000 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>

Commit 65d8fc7 ("futex: Remove requirement for lock_page() in get_futex_key()") removed an unnecessary lock_page() with the side-effect that page->mapping needed to be treated very carefully. Two defensive warnings were added in case any assumption was missed and the first warning assumed a correct application would not alter a mapping backing a futex key. Since merging, it has not triggered for any unexpected case but Mark Rutland reported the following bug triggering due to the first warning. kernel BUG at kernel/futex.c:679! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 3695 Comm: syz-executor1 Not tainted 4.13.0-rc3-00020-g307fec773ba3 #3 Hardware name: linux,dummy-virt (DT) task: ffff80001e271780 task.stack: ffff000010908000 PC is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 LR is at get_futex_key+0x6a4/0xcf0 kernel/futex.c:679 pc : [<ffff00000821ac14>] lr : [<ffff00000821ac14>] pstate: 80000145 The fact that it's a bug instead of a warning was due to an unrelated arm64 problem, but the warning itself triggered because the underlying mapping changed. This is an application issue but from a kernel perspective it's a recoverable situation and the warning is unnecessary so this patch removes the warning. The warning may potentially be triggered with the following test program from Mark although it may be necessary to adjust NR_FUTEX_THREADS to be a value smaller than the number of CPUs in the system. #include <linux/futex.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <sys/syscall.h> #include <sys/time.h> #include <unistd.h> #define NR_FUTEX_THREADS 16 pthread_t threads[NR_FUTEX_THREADS]; void *mem; #define MEM_PROT (PROT_READ | PROT_WRITE) #define MEM_SIZE 65536 static int futex_wrapper(int *uaddr, int op, int val, const struct timespec *timeout, int *uaddr2, int val3) { syscall(SYS_futex, uaddr, op, val, timeout, uaddr2, val3); } void *poll_futex(void *unused) { for (;;) { futex_wrapper(mem, FUTEX_CMP_REQUEUE_PI, 1, NULL, mem + 4, 1); } } int main(int argc, char *argv[]) { int i; mem = mmap(NULL, MEM_SIZE, MEM_PROT, MAP_SHARED | MAP_ANONYMOUS, -1, 0); printf("Mapping @ %p\n", mem); printf("Creating futex threads...\n"); for (i = 0; i < NR_FUTEX_THREADS; i++) pthread_create(&threads[i], NULL, poll_futex, NULL); printf("Flipping mapping...\n"); for (;;) { mmap(mem, MEM_SIZE, MEM_PROT, MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS, -1, 0); } return 0; } Reported-and-tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org # 4.7+ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The Flower app may receive a request to update the MTU of a representor netdev upon receipt of a control message from the firmware. This requires the RTNL lock which needs to be taken outside of the packet processing path. As a handling of this correctly seems a little to invasive for a fix simply skip setting the MTU for now. Relevant backtrace: [ 1496.288489] BUG: scheduling while atomic: kworker/0:3/373/0x00000100 [ 1496.294911] dca syscopyarea sysfillrect sysimgblt fb_sys_fops ptp drm mxm_wmi ahci pps_core libahci i2c_algo_bit wmi [last unloaded: nfp] [ 1496.294918] CPU: 0 PID: 373 Comm: kworker/0:3 Tainted: G OE 4.13.0-rc3+ #3 [ 1496.294919] Hardware name: Supermicro X10DRi/X10DRi, BIOS 2.0 12/28/2015 [ 1496.294923] Workqueue: events work_for_cpu_fn [ 1496.294924] Call Trace: [ 1496.294927] <IRQ> [ 1496.294931] dump_stack+0x63/0x82 [ 1496.294935] __schedule_bug+0x54/0x70 [ 1496.294937] __schedule+0x62f/0x890 [ 1496.294941] ? intel_unmap_sg+0x90/0x90 [ 1496.294942] schedule+0x36/0x80 [ 1496.294943] schedule_preempt_disabled+0xe/0x10 [ 1496.294945] __mutex_lock.isra.2+0x445/0x4a0 [ 1496.294947] ? device_is_rmrr_locked+0x12/0x50 [ 1496.294950] ? kfree+0x162/0x170 [ 1496.294952] ? device_is_rmrr_locked+0x12/0x50 [ 1496.294953] ? iommu_should_identity_map+0x50/0xe0 [ 1496.294954] __mutex_lock_slowpath+0x13/0x20 [ 1496.294955] ? iommu_no_mapping+0x48/0xd0 [ 1496.294956] ? __mutex_lock_slowpath+0x13/0x20 [ 1496.294957] mutex_lock+0x2f/0x40 [ 1496.294960] rtnl_lock+0x15/0x20 [ 1496.294979] nfp_flower_cmsg_rx+0xc8/0x150 [nfp] [ 1496.294986] nfp_ctrl_poll+0x286/0x350 [nfp] [ 1496.294989] tasklet_action+0xf6/0x110 [ 1496.294992] __do_softirq+0xed/0x278 [ 1496.294993] irq_exit+0xb6/0xc0 [ 1496.294994] do_IRQ+0x4f/0xd0 [ 1496.294996] common_interrupt+0x89/0x89 Fixes: 948faa4 ("nfp: add support for control messages for flower app") Signed-off-by: Simon Horman <simon.horman@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>

syszkaller team reported another problem in DCCP [1] Problem here is that the structure holding RTO timer (ccid2_hc_tx_rto_expire() handler) is freed too soon. We can not use del_timer_sync() to cancel the timer since this timer wants to grab socket lock (that would risk a dead lock) Solution is to defer the freeing of memory when all references to the socket were released. Socket timers do own a reference, so this should fix the issue. [1] ================================================================== BUG: KASAN: use-after-free in ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144 Read of size 4 at addr ffff8801d2660540 by task kworker/u4:7/3365 CPU: 1 PID: 3365 Comm: kworker/u4:7 Not tainted 4.13.0-rc4+ #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound call_usermodehelper_exec_work Call Trace: <IRQ> __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x24e/0x340 mm/kasan/report.c:409 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 ccid2_hc_tx_rto_expire+0x51c/0x5c0 net/dccp/ccids/ccid2.c:144 call_timer_fn+0x233/0x830 kernel/time/timer.c:1268 expire_timers kernel/time/timer.c:1307 [inline] __run_timers+0x7fd/0xb90 kernel/time/timer.c:1601 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:638 [inline] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:1044 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:702 RIP: 0010:arch_local_irq_enable arch/x86/include/asm/paravirt.h:824 [inline] RIP: 0010:__raw_write_unlock_irq include/linux/rwlock_api_smp.h:267 [inline] RIP: 0010:_raw_write_unlock_irq+0x56/0x70 kernel/locking/spinlock.c:343 RSP: 0018:ffff8801cd50eaa8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10 RAX: dffffc0000000000 RBX: ffffffff85a090c0 RCX: 0000000000000006 RDX: 1ffffffff0b595f3 RSI: 1ffff1003962f989 RDI: ffffffff85acaf98 RBP: ffff8801cd50eab0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801cc96ea60 R13: dffffc0000000000 R14: ffff8801cc96e4c0 R15: ffff8801cc96e4c0 </IRQ> release_task+0xe9e/0x1a40 kernel/exit.c:220 wait_task_zombie kernel/exit.c:1162 [inline] wait_consider_task+0x29b8/0x33c0 kernel/exit.c:1389 do_wait_thread kernel/exit.c:1452 [inline] do_wait+0x441/0xa90 kernel/exit.c:1523 kernel_wait4+0x1f5/0x370 kernel/exit.c:1665 SYSC_wait4+0x134/0x140 kernel/exit.c:1677 SyS_wait4+0x2c/0x40 kernel/exit.c:1673 call_usermodehelper_exec_sync kernel/kmod.c:286 [inline] call_usermodehelper_exec_work+0x1a0/0x2c0 kernel/kmod.c:323 process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2097 worker_thread+0x223/0x1860 kernel/workqueue.c:2231 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:425 Allocated by task 21267: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x127/0x750 mm/slab.c:3561 ccid_new+0x20e/0x390 net/dccp/ccid.c:151 dccp_hdlr_ccid+0x27/0x140 net/dccp/feat.c:44 __dccp_feat_activate+0x142/0x2a0 net/dccp/feat.c:344 dccp_feat_activate_values+0x34e/0xa90 net/dccp/feat.c:1538 dccp_rcv_request_sent_state_process net/dccp/input.c:472 [inline] dccp_rcv_state_process+0xed1/0x1620 net/dccp/input.c:677 dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679 sk_backlog_rcv include/net/sock.h:911 [inline] __release_sock+0x124/0x360 net/core/sock.c:2269 release_sock+0xa4/0x2a0 net/core/sock.c:2784 inet_wait_for_connect net/ipv4/af_inet.c:557 [inline] __inet_stream_connect+0x671/0xf00 net/ipv4/af_inet.c:643 inet_stream_connect+0x58/0xa0 net/ipv4/af_inet.c:682 SYSC_connect+0x204/0x470 net/socket.c:1642 SyS_connect+0x24/0x30 net/socket.c:1623 entry_SYSCALL_64_fastpath+0x1f/0xbe Freed by task 3049: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3503 [inline] kmem_cache_free+0x77/0x280 mm/slab.c:3763 ccid_hc_tx_delete+0xc5/0x100 net/dccp/ccid.c:190 dccp_destroy_sock+0x1d1/0x2b0 net/dccp/proto.c:225 inet_csk_destroy_sock+0x166/0x3f0 net/ipv4/inet_connection_sock.c:833 dccp_done+0xb7/0xd0 net/dccp/proto.c:145 dccp_time_wait+0x13d/0x300 net/dccp/minisocks.c:72 dccp_rcv_reset+0x1d1/0x5b0 net/dccp/input.c:160 dccp_rcv_state_process+0x8fc/0x1620 net/dccp/input.c:663 dccp_v4_do_rcv+0xeb/0x160 net/dccp/ipv4.c:679 sk_backlog_rcv include/net/sock.h:911 [inline] __sk_receive_skb+0x33e/0xc00 net/core/sock.c:521 dccp_v4_rcv+0xef1/0x1c00 net/dccp/ipv4.c:871 ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216 NF_HOOK include/linux/netfilter.h:248 [inline] ip_local_deliver+0x1ce/0x6d0 net/ipv4/ip_input.c:257 dst_input include/net/dst.h:477 [inline] ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397 NF_HOOK include/linux/netfilter.h:248 [inline] ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488 __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4417 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4455 process_backlog+0x203/0x740 net/core/dev.c:5130 napi_poll net/core/dev.c:5527 [inline] net_rx_action+0x792/0x1910 net/core/dev.c:5593 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284 The buggy address belongs to the object at ffff8801d2660100 which belongs to the cache ccid2_hc_tx_sock of size 1240 The buggy address is located 1088 bytes inside of 1240-byte region [ffff8801d2660100, ffff8801d26605d8) The buggy address belongs to the page: page:ffffea0007499800 count:1 mapcount:0 mapping:ffff8801d2660100 index:0x0 compound_mapcount: 0 flags: 0x200000000008100(slab|head) raw: 0200000000008100 ffff8801d2660100 0000000000000000 0000000100000005 raw: ffffea00075271a0 ffffea0007538820 ffff8801d3aef9c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d2660400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d2660480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d2660500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d2660580: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ffff8801d2660600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: David S. Miller <davem@davemloft.net>

…buffer Since we split the scsi_request out of struct request bsg fails to provide a reply-buffer for the drivers. This was done via the pointer for sense-data, that is not preallocated anymore. Failing to allocate/assign it results in illegal dereferences because LLDs use this pointer unquestioned. An example panic on s390x, using the zFCP driver, looks like this (I had debugging on, otherwise NULL-pointer dereferences wouldn't even panic on s390x): Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6403 Fault in home space mode while using kernel ASCE. AS:0000000001590007 R3:0000000000000024 Oops: 0038 ilc:2 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: <Long List> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.12.0-bsg-regression+ #3 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) task: 0000000065cb0100 task.stack: 0000000065cb4000 Krnl PSW : 0704e00180000000 000003ff801e4156 (zfcp_fc_ct_els_job_handler+0x16/0x58 [zfcp]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000001 000000005fa9d0d0 000000005fa9d078 0000000000e16866 000003ff00000290 6b6b6b6b6b6b6b6b 0000000059f78f00 000000000000000f 00000000593a0958 00000000593a0958 0000000060d88800 000000005ddd4c38 0000000058b50100 07000000659cba08 000003ff801e8556 00000000659cb9a8 Krnl Code: 000003ff801e4146: e31020500004 lg %r1,80(%r2) 000003ff801e414c: 58402040 l %r4,64(%r2) #000003ff801e4150: e35020200004 lg %r5,32(%r2) >000003ff801e4156: 50405004 st %r4,4(%r5) 000003ff801e415a: e54c50080000 mvhi 8(%r5),0 000003ff801e4160: e33010280012 lt %r3,40(%r1) 000003ff801e4166: a718fffb lhi %r1,-5 000003ff801e416a: 1803 lr %r0,%r3 Call Trace: ([<000003ff801e8556>] zfcp_fsf_req_complete+0x726/0x768 [zfcp]) [<000003ff801ea82a>] zfcp_fsf_reqid_check+0x102/0x180 [zfcp] [<000003ff801eb980>] zfcp_qdio_int_resp+0x230/0x278 [zfcp] [<00000000009b91b6>] qdio_kick_handler+0x2ae/0x2c8 [<00000000009b9e3e>] __tiqdio_inbound_processing+0x406/0xc10 [<00000000001684c2>] tasklet_action+0x15a/0x1d8 [<0000000000bd28ec>] __do_softirq+0x3ec/0x848 [<00000000001675a4>] irq_exit+0x74/0xf8 [<000000000010dd6a>] do_IRQ+0xba/0xf0 [<0000000000bd19e8>] io_int_handler+0x104/0x2d4 [<00000000001033b6>] enabled_wait+0xb6/0x188 ([<000000000010339e>] enabled_wait+0x9e/0x188) [<000000000010396a>] arch_cpu_idle+0x32/0x50 [<0000000000bd0112>] default_idle_call+0x52/0x68 [<00000000001cd0fa>] do_idle+0x102/0x188 [<00000000001cd41e>] cpu_startup_entry+0x3e/0x48 [<0000000000118c64>] smp_start_secondary+0x11c/0x130 [<0000000000bd2016>] restart_int_handler+0x62/0x78 [<0000000000000000>] (null) INFO: lockdep is turned off. Last Breaking-Event-Address: [<000003ff801e41d6>] zfcp_fc_ct_job_handler+0x3e/0x48 [zfcp] Kernel panic - not syncing: Fatal exception in interrupt This patch moves bsg-lib to allocate and setup struct bsg_job ahead of time, including the allocation of a buffer for the reply-data. This means, struct bsg_job is not allocated separately anymore, but as part of struct request allocation - similar to struct scsi_cmd. Reflect this in the function names that used to handle creation/destruction of struct bsg_job. Reported-by: Steffen Maier <maier@linux.vnet.ibm.com> Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com> Fixes: 82ed4db ("block: split scsi_request out of struct request") Cc: <stable@vger.kernel.org> #4.11+ Signed-off-by: Jens Axboe <axboe@kernel.dk>

Recently the following BUG was reported: Injecting memory failure for pfn 0x3c0000 at process virtual address 0x7fe300000000 Memory failure: 0x3c0000: recovery action for huge page: Recovered BUG: unable to handle kernel paging request at ffff8dfcc0003000 IP: gup_pgd_range+0x1f0/0xc20 PGD 17ae72067 P4D 17ae72067 PUD 0 Oops: 0000 [SELinuxProject#1] SMP PTI ... CPU: 3 PID: 5467 Comm: hugetlb_1gb Not tainted 4.15.0-rc8-mm1-abc+ SELinuxProject#3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014 You can easily reproduce this by calling madvise(MADV_HWPOISON) twice on a 1GB hugepage. This happens because get_user_pages_fast() is not aware of a migration entry on pud that was created in the 1st madvise() event. I think that conversion to pud-aligned migration entry is working, but other MM code walking over page table isn't prepared for it. We need some time and effort to make all this work properly, so this patch avoids the reported bug by just disabling error handling for 1GB hugepage. [n-horiguchi@ah.jp.nec.com: v2] Link: http://lkml.kernel.org/r/1517284444-18149-1-git-send-email-n-horiguchi@ah.jp.nec.com Link: http://lkml.kernel.org/r/1517207283-15769-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Punit Agrawal <punit.agrawal@arm.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "kexec_file, x86, powerpc: refactoring for other architecutres", v2. This is a preparatory patchset for adding kexec_file support on arm64. It was originally included in a arm64 patch set[1], but Philipp is also working on their kexec_file support on s390[2] and some changes are now conflicting. So these common parts were extracted and put into a separate patch set for better integration. What's more, my original patch#4 was split into a few small chunks for easier review after Dave's comment. As such, the resulting code is basically identical with my original, and the only *visible* differences are: - renaming of _kexec_kernel_image_probe() and _kimage_file_post_load_cleanup() - change one of types of arguments at prepare_elf64_headers() Those, unfortunately, require a couple of trivial changes on the rest (SELinuxProject#1, SELinuxProject#6 to SELinuxProject#13) of my arm64 kexec_file patch set[1]. Patch SELinuxProject#1 allows making a use of purgatory optional, particularly useful for arm64. Patch SELinuxProject#2 commonalizes arch_kexec_kernel_{image_probe, image_load, verify_sig}() and arch_kimage_file_post_load_cleanup() across architectures. Patches SELinuxProject#3-SELinuxProject#7 are also intended to generalize parse_elf64_headers(), along with exclude_mem_range(), to be made best re-use of. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/561182.html [2] http://lkml.iu.edu//hypermail/linux/kernel/1802.1/02596.html This patch (of 7): On arm64, crash dump kernel's usable memory is protected by *unmapping* it from kernel virtual space unlike other architectures where the region is just made read-only. It is highly unlikely that the region is accidentally corrupted and this observation rationalizes that digest check code can also be dropped from purgatory. The resulting code is so simple as it doesn't require a bit ugly re-linking/relocation stuff, i.e. arch_kexec_apply_relocations_add(). Please see: http://lists.infradead.org/pipermail/linux-arm-kernel/2017-December/545428.html All that the purgatory does is to shuffle arguments and jump into a new kernel, while we still need to have some space for a hash value (purgatory_sha256_digest) which is never checked against. As such, it doesn't make sense to have trampline code between old kernel and new kernel on arm64. This patch introduces a new configuration, ARCH_HAS_KEXEC_PURGATORY, and allows related code to be compiled in only if necessary. [takahiro.akashi@linaro.org: fix trivial screwup] Link: http://lkml.kernel.org/r/20180309093346.GF25863@linaro.org Link: http://lkml.kernel.org/r/20180306102303.9063-2-takahiro.akashi@linaro.org Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Acked-by: Dave Young <dyoung@redhat.com> Tested-by: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "kexec_file: Clean up purgatory load", v2. Following the discussion with Dave and AKASHI, here are the common code patches extracted from my recent patch set (Add kexec_file_load support to s390) [1]. The patches were extracted to allow upstream integration together with AKASHI's common code patches before the arch code gets adjusted to the new base. The reason for this series is to prepare common code for adding kexec_file_load to s390 as well as cleaning up the mis-use of the sh_offset field during purgatory load. In detail this series contains: Patch SELinuxProject#1&2: Minor cleanups/fixes. Patch SELinuxProject#3-9: Clean up the purgatory load/relocation code. Especially remove the mis-use of the purgatory_info->sechdrs->sh_offset field, currently holding a pointer into either kexec_purgatory (ro) or purgatory_buf (rw) depending on the section. With these patches the section address will be calculated verbosely and sh_offset will contain the offset of the section in the stripped purgatory binary (purgatory_buf). Patch SELinuxProject#10: Allows architectures to set the purgatory load address. This patch is important for s390 as the kernel and purgatory have to be loaded to fixed addresses. In current code this is impossible as the purgatory load is opaque to the architecture. Patch SELinuxProject#11: Moves x86 purgatories sha implementation to common lib/ directory to allow reuse in other architectures. This patch (of 11) When building the kernel with CONFIG_KEXEC_FILE enabled gcc prints a compile warning multiple times. In file included from <path>/linux/init/initramfs.c:526:0: <path>/include/linux/kexec.h:120:9: warning: `struct kimage' declared inside parameter list [enabled by default] unsigned long cmdline_len); ^ This is because the typedefs for kexec_file_load uses struct kimage before it is declared. Fix this by simply forward declaring struct kimage. Link: http://lkml.kernel.org/r/20180321112751.22196-2-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch fixes the race between netvsc_probe() and rndis_set_subchannel(), which can cause a deadlock. These are the related 3 paths which show the deadlock: path #1: Workqueue: hv_vmbus_con vmbus_onmessage_work [hv_vmbus] Call Trace: schedule schedule_preempt_disabled __mutex_lock __device_attach bus_probe_device device_add vmbus_device_register vmbus_onoffer vmbus_onmessage_work process_one_work worker_thread kthread ret_from_fork path #2: schedule schedule_preempt_disabled __mutex_lock netvsc_probe vmbus_probe really_probe __driver_attach bus_for_each_dev driver_attach_async async_run_entry_fn process_one_work worker_thread kthread ret_from_fork path #3: Workqueue: events netvsc_subchan_work [hv_netvsc] Call Trace: schedule rndis_set_subchannel netvsc_subchan_work process_one_work worker_thread kthread ret_from_fork Before path #1 finishes, path #2 can start to run, because just before the "bus_probe_device(dev);" in device_add() in path #1, there is a line "object_uevent(&dev->kobj, KOBJ_ADD);", so systemd-udevd can immediately try to load hv_netvsc and hence path #2 can start to run. Next, path #2 offloads the subchannal's initialization to a workqueue, i.e. path #3, so we can end up in a deadlock situation like this: Path #2 gets the device lock, and is trying to get the rtnl lock; Path #3 gets the rtnl lock and is waiting for all the subchannel messages to be processed; Path #1 is trying to get the device lock, but since #2 is not releasing the device lock, path #1 has to sleep; since the VMBus messages are processed one by one, this means the sub-channel messages can't be procedded, so #3 has to sleep with the rtnl lock held, and finally #2 has to sleep... Now all the 3 paths are sleeping and we hit the deadlock. With the patch, we can make sure #2 gets both the device lock and the rtnl lock together, gets its job done, and releases the locks, so #1 and #3 will not be blocked for ever. Fixes: 8195b13 ("hv_netvsc: fix deadlock on hotplug") Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>

…equests Currently, nouveau uses the generic drm_fb_helper_output_poll_changed() function provided by DRM as it's output_poll_changed callback. Unfortunately however, this function doesn't grab runtime PM references early enough and even if it did-we can't block waiting for the device to resume in output_poll_changed() since it's very likely that we'll need to grab the fb_helper lock at some point during the runtime resume process. This currently results in deadlocking like so: [ 246.669625] INFO: task kworker/4:0:37 blocked for more than 120 seconds. [ 246.673398] Not tainted 4.18.0-rc5Lyude-Test+ #2 [ 246.675271] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 246.676527] kworker/4:0 D 0 37 2 0x80000000 [ 246.677580] Workqueue: events output_poll_execute [drm_kms_helper] [ 246.678704] Call Trace: [ 246.679753] __schedule+0x322/0xaf0 [ 246.680916] schedule+0x33/0x90 [ 246.681924] schedule_preempt_disabled+0x15/0x20 [ 246.683023] __mutex_lock+0x569/0x9a0 [ 246.684035] ? kobject_uevent_env+0x117/0x7b0 [ 246.685132] ? drm_fb_helper_hotplug_event.part.28+0x20/0xb0 [drm_kms_helper] [ 246.686179] mutex_lock_nested+0x1b/0x20 [ 246.687278] ? mutex_lock_nested+0x1b/0x20 [ 246.688307] drm_fb_helper_hotplug_event.part.28+0x20/0xb0 [drm_kms_helper] [ 246.689420] drm_fb_helper_output_poll_changed+0x23/0x30 [drm_kms_helper] [ 246.690462] drm_kms_helper_hotplug_event+0x2a/0x30 [drm_kms_helper] [ 246.691570] output_poll_execute+0x198/0x1c0 [drm_kms_helper] [ 246.692611] process_one_work+0x231/0x620 [ 246.693725] worker_thread+0x214/0x3a0 [ 246.694756] kthread+0x12b/0x150 [ 246.695856] ? wq_pool_ids_show+0x140/0x140 [ 246.696888] ? kthread_create_worker_on_cpu+0x70/0x70 [ 246.697998] ret_from_fork+0x3a/0x50 [ 246.699034] INFO: task kworker/0:1:60 blocked for more than 120 seconds. [ 246.700153] Not tainted 4.18.0-rc5Lyude-Test+ #2 [ 246.701182] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 246.702278] kworker/0:1 D 0 60 2 0x80000000 [ 246.703293] Workqueue: pm pm_runtime_work [ 246.704393] Call Trace: [ 246.705403] __schedule+0x322/0xaf0 [ 246.706439] ? wait_for_completion+0x104/0x190 [ 246.707393] schedule+0x33/0x90 [ 246.708375] schedule_timeout+0x3a5/0x590 [ 246.709289] ? mark_held_locks+0x58/0x80 [ 246.710208] ? _raw_spin_unlock_irq+0x2c/0x40 [ 246.711222] ? wait_for_completion+0x104/0x190 [ 246.712134] ? trace_hardirqs_on_caller+0xf4/0x190 [ 246.713094] ? wait_for_completion+0x104/0x190 [ 246.713964] wait_for_completion+0x12c/0x190 [ 246.714895] ? wake_up_q+0x80/0x80 [ 246.715727] ? get_work_pool+0x90/0x90 [ 246.716649] flush_work+0x1c9/0x280 [ 246.717483] ? flush_workqueue_prep_pwqs+0x1b0/0x1b0 [ 246.718442] __cancel_work_timer+0x146/0x1d0 [ 246.719247] cancel_delayed_work_sync+0x13/0x20 [ 246.720043] drm_kms_helper_poll_disable+0x1f/0x30 [drm_kms_helper] [ 246.721123] nouveau_pmops_runtime_suspend+0x3d/0xb0 [nouveau] [ 246.721897] pci_pm_runtime_suspend+0x6b/0x190 [ 246.722825] ? pci_has_legacy_pm_support+0x70/0x70 [ 246.723737] __rpm_callback+0x7a/0x1d0 [ 246.724721] ? pci_has_legacy_pm_support+0x70/0x70 [ 246.725607] rpm_callback+0x24/0x80 [ 246.726553] ? pci_has_legacy_pm_support+0x70/0x70 [ 246.727376] rpm_suspend+0x142/0x6b0 [ 246.728185] pm_runtime_work+0x97/0xc0 [ 246.728938] process_one_work+0x231/0x620 [ 246.729796] worker_thread+0x44/0x3a0 [ 246.730614] kthread+0x12b/0x150 [ 246.731395] ? wq_pool_ids_show+0x140/0x140 [ 246.732202] ? kthread_create_worker_on_cpu+0x70/0x70 [ 246.732878] ret_from_fork+0x3a/0x50 [ 246.733768] INFO: task kworker/4:2:422 blocked for more than 120 seconds. [ 246.734587] Not tainted 4.18.0-rc5Lyude-Test+ #2 [ 246.735393] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 246.736113] kworker/4:2 D 0 422 2 0x80000080 [ 246.736789] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper] [ 246.737665] Call Trace: [ 246.738490] __schedule+0x322/0xaf0 [ 246.739250] schedule+0x33/0x90 [ 246.739908] rpm_resume+0x19c/0x850 [ 246.740750] ? finish_wait+0x90/0x90 [ 246.741541] __pm_runtime_resume+0x4e/0x90 [ 246.742370] nv50_disp_atomic_commit+0x31/0x210 [nouveau] [ 246.743124] drm_atomic_commit+0x4a/0x50 [drm] [ 246.743775] restore_fbdev_mode_atomic+0x1c8/0x240 [drm_kms_helper] [ 246.744603] restore_fbdev_mode+0x31/0x140 [drm_kms_helper] [ 246.745373] drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xb0 [drm_kms_helper] [ 246.746220] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper] [ 246.746884] drm_fb_helper_hotplug_event.part.28+0x96/0xb0 [drm_kms_helper] [ 246.747675] drm_fb_helper_output_poll_changed+0x23/0x30 [drm_kms_helper] [ 246.748544] drm_kms_helper_hotplug_event+0x2a/0x30 [drm_kms_helper] [ 246.749439] nv50_mstm_hotplug+0x15/0x20 [nouveau] [ 246.750111] drm_dp_send_link_address+0x177/0x1c0 [drm_kms_helper] [ 246.750764] drm_dp_check_and_send_link_address+0xa8/0xd0 [drm_kms_helper] [ 246.751602] drm_dp_mst_link_probe_work+0x51/0x90 [drm_kms_helper] [ 246.752314] process_one_work+0x231/0x620 [ 246.752979] worker_thread+0x44/0x3a0 [ 246.753838] kthread+0x12b/0x150 [ 246.754619] ? wq_pool_ids_show+0x140/0x140 [ 246.755386] ? kthread_create_worker_on_cpu+0x70/0x70 [ 246.756162] ret_from_fork+0x3a/0x50 [ 246.756847] Showing all locks held in the system: [ 246.758261] 3 locks held by kworker/4:0/37: [ 246.759016] #0: 00000000f8df4d2d ((wq_completion)"events"){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.759856] #1: 00000000e6065461 ((work_completion)(&(&dev->mode_config.output_poll_work)->work)){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.760670] #2: 00000000cb66735f (&helper->lock){+.+.}, at: drm_fb_helper_hotplug_event.part.28+0x20/0xb0 [drm_kms_helper] [ 246.761516] 2 locks held by kworker/0:1/60: [ 246.762274] #0: 00000000fff6be0f ((wq_completion)"pm"){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.762982] #1: 000000005ab44fb4 ((work_completion)(&dev->power.work)){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.763890] 1 lock held by khungtaskd/64: [ 246.764664] #0: 000000008cb8b5c3 (rcu_read_lock){....}, at: debug_show_all_locks+0x23/0x185 [ 246.765588] 5 locks held by kworker/4:2/422: [ 246.766440] #0: 00000000232f0959 ((wq_completion)"events_long"){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.767390] #1: 00000000bb59b134 ((work_completion)(&mgr->work)){+.+.}, at: process_one_work+0x1b3/0x620 [ 246.768154] #2: 00000000cb66735f (&helper->lock){+.+.}, at: drm_fb_helper_restore_fbdev_mode_unlocked+0x4c/0xb0 [drm_kms_helper] [ 246.768966] #3: 000000004c8f0b6b (crtc_ww_class_acquire){+.+.}, at: restore_fbdev_mode_atomic+0x4b/0x240 [drm_kms_helper] [ 246.769921] #4: 000000004c34a296 (crtc_ww_class_mutex){+.+.}, at: drm_modeset_backoff+0x8a/0x1b0 [drm] [ 246.770839] 1 lock held by dmesg/1038: [ 246.771739] 2 locks held by zsh/1172: [ 246.772650] #0: 00000000836d0438 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 [ 246.773680] #1: 000000001f4f4d48 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0xc1/0x870 [ 246.775522] ============================================= After trying dozens of different solutions, I found one very simple one that should also have the benefit of preventing us from having to fight locking for the rest of our lives. So, we work around these deadlocks by deferring all fbcon hotplug events that happen after the runtime suspend process starts until after the device is resumed again. Changes since v7: - Fixup commit message - Daniel Vetter Changes since v6: - Remove unused nouveau_fbcon_hotplugged_in_suspend() - Ilia Changes since v5: - Come up with the (hopefully final) solution for solving this dumb problem, one that is a lot less likely to cause issues with locking in the future. This should work around all deadlock conditions with fbcon brought up thus far. Changes since v4: - Add nouveau_fbcon_hotplugged_in_suspend() to workaround deadlock condition that Lukas described - Just move all of this out of drm_fb_helper. It seems that other DRM drivers have already figured out other workarounds for this. If other drivers do end up needing this in the future, we can just move this back into drm_fb_helper again. Changes since v3: - Actually check if fb_helper is NULL in both new helpers - Actually check drm_fbdev_emulation in both new helpers - Don't fire off a fb_helper hotplug unconditionally; only do it if the following conditions are true (as otherwise, calling this in the wrong spot will cause Bad Things to happen): - fb_helper hotplug handling was actually inhibited previously - fb_helper actually has a delayed hotplug pending - fb_helper is actually bound - fb_helper is actually initialized - Add __must_check to drm_fb_helper_suspend_hotplug(). There's no situation where a driver would actually want to use this without checking the return value, so enforce that - Rewrite and clarify the documentation for both helpers. - Make sure to return true in the drm_fb_helper_suspend_hotplug() stub that's provided in drm_fb_helper.h when CONFIG_DRM_FBDEV_EMULATION isn't enabled - Actually grab the toplevel fb_helper lock in drm_fb_helper_resume_hotplug(), since it's possible other activity (such as a hotplug) could be going on at the same time the driver calls drm_fb_helper_resume_hotplug(). We need this to check whether or not drm_fb_helper_hotplug_event() needs to be called anyway Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Karol Herbst <kherbst@redhat.com> Acked-by: Daniel Vetter <daniel@ffwll.ch> Cc: stable@vger.kernel.org Cc: Lukas Wunner <lukas@wunner.de> Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

Previously if we couldn't find an entry in the cache and we failed to allocate memory for a new cache entry we would fail the network object label lookup; this is obviously not ideal. This patch fixes this so that we return the object label even if we can't cache the object at this point in time due to memory pressure. The GitHub issue tracker is below: * SELinuxProject/selinux-kernel#3 Signed-off-by: Paul Moore <paul@paul-moore.com>

Previously if we couldn't find an entry in the cache and we failed to allocate memory for a new cache entry we would fail the network object label lookup; this is obviously not ideal. This patch fixes this so that we return the object label even if we can't cache the object at this point in time due to memory pressure. The GitHub issue tracker is below: * SELinuxProject/selinux-kernel#3 Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Reinazhard <reinazhard@gmail.com>

tl;dr: The Enhanced IBRS mitigation for Spectre v2 does not work as documented for RET instructions after VM exits. Mitigate it with a new one-entry RSB stuffing mechanism and a new LFENCE. == Background == Indirect Branch Restricted Speculation (IBRS) was designed to help mitigate Branch Target Injection and Speculative Store Bypass, i.e. Spectre, attacks. IBRS prevents software run in less privileged modes from affecting branch prediction in more privileged modes. IBRS requires the MSR to be written on every privilege level change. To overcome some of the performance issues of IBRS, Enhanced IBRS was introduced. eIBRS is an "always on" IBRS, in other words, just turn it on once instead of writing the MSR on every privilege level change. When eIBRS is enabled, more privileged modes should be protected from less privileged modes, including protecting VMMs from guests. == Problem == Here's a simplification of how guests are run on Linux' KVM: void run_kvm_guest(void) { // Prepare to run guest VMRESUME(); // Clean up after guest runs } The execution flow for that would look something like this to the processor: 1. Host-side: call run_kvm_guest() 2. Host-side: VMRESUME 3. Guest runs, does "CALL guest_function" 4. VM exit, host runs again 5. Host might make some "cleanup" function calls 6. Host-side: RET from run_kvm_guest() Now, when back on the host, there are a couple of possible scenarios of post-guest activity the host needs to do before executing host code: * on pre-eIBRS hardware (legacy IBRS, or nothing at all), the RSB is not touched and Linux has to do a 32-entry stuffing. * on eIBRS hardware, VM exit with IBRS enabled, or restoring the host IBRS=1 shortly after VM exit, has a documented side effect of flushing the RSB except in this PBRSB situation where the software needs to stuff the last RSB entry "by hand". IOW, with eIBRS supported, host RET instructions should no longer be influenced by guest behavior after the host retires a single CALL instruction. However, if the RET instructions are "unbalanced" with CALLs after a VM exit as is the RET in #6, it might speculatively use the address for the instruction after the CALL in #3 as an RSB prediction. This is a problem since the (untrusted) guest controls this address. Balanced CALL/RET instruction pairs such as in step #5 are not affected. == Solution == The PBRSB issue affects a wide variety of Intel processors which support eIBRS. But not all of them need mitigation. Today, X86_FEATURE_RSB_VMEXIT triggers an RSB filling sequence that mitigates PBRSB. Systems setting RSB_VMEXIT need no further mitigation - i.e., eIBRS systems which enable legacy IBRS explicitly. However, such systems (X86_FEATURE_IBRS_ENHANCED) do not set RSB_VMEXIT and most of them need a new mitigation. Therefore, introduce a new feature flag X86_FEATURE_RSB_VMEXIT_LITE which triggers a lighter-weight PBRSB mitigation versus RSB_VMEXIT. The lighter-weight mitigation performs a CALL instruction which is immediately followed by a speculative execution barrier (INT3). This steers speculative execution to the barrier -- just like a retpoline -- which ensures that speculation can never reach an unbalanced RET. Then, ensure this CALL is retired before continuing execution with an LFENCE. In other words, the window of exposure is opened at VM exit where RET behavior is troublesome. While the window is open, force RSB predictions sampling for RET targets to a dead end at the INT3. Close the window with the LFENCE. There is a subset of eIBRS systems which are not vulnerable to PBRSB. Add these systems to the cpu_vuln_whitelist[] as NO_EIBRS_PBRSB. Future systems that aren't vulnerable will set ARCH_CAP_PBRSB_NO. [ bp: Massage, incorporate review comments from Andy Cooper. ] Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com> Co-developed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de>

When use 'echo c > /proc/sysrq-trigger' to trigger kdump, riscv_crash_save_regs() will be called to save regs for vmcore, we found "epc" value 00ffffffa5537400 is not a valid kernel virtual address, but is a user virtual address. Other regs(eg, ra, sp, gp...) are correct kernel virtual address. Actually 0x00ffffffb0dd9400 is the user mode PC of 'PID: 113 Comm: sh', which is saved in the task's stack. [ 21.201701] CPU: 0 PID: 113 Comm: sh Kdump: loaded Not tainted 5.18.9 #45 [ 21.201979] Hardware name: riscv-virtio,qemu (DT) [ 21.202160] epc : 00ffffffa5537400 ra : ffffffff80088640 sp : ff20000010333b90 [ 21.202435] gp : ffffffff810dde38 tp : ff6000000226c200 t0 : ffffffff8032be7c [ 21.202707] t1 : 0720072007200720 t2 : 30203a7375746174 s0 : ff20000010333cf0 [ 21.202973] s1 : 0000000000000000 a0 : ff20000010333b98 a1 : 0000000000000001 [ 21.203243] a2 : 0000000000000010 a3 : 0000000000000000 a4 : 28c8f0aeffea4e00 [ 21.203519] a5 : 28c8f0aeffea4e00 a6 : 0000000000000009 a7 : ffffffff8035c9b8 [ 21.203794] s2 : ffffffff810df0a8 s3 : ffffffff810df718 s4 : ff20000010333b98 [ 21.204062] s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80c4a468 [ 21.204331] s8 : 00ffffffef451410 s9 : 0000000000000007 s10: 00aaaaaac0510700 [ 21.204606] s11: 0000000000000001 t3 : ff60000001218f00 t4 : ff60000001218f00 [ 21.204876] t5 : ff60000001218000 t6 : ff200000103338b8 [ 21.205079] status: 0000000200000020 badaddr: 0000000000000000 cause: 0000000000000008 With the incorrect PC, the backtrace showed by crash tool as below, the first stack frame is abnormal, crash> bt PID: 113 TASK: ff60000002269600 CPU: 0 COMMAND: "sh" #0 [ff2000001039bb90] __efistub_.Ldebug_info0 at 00ffffffa5537400 <-- Abnormal #1 [ff2000001039bcf0] panic at ffffffff806578ba #2 [ff2000001039bd50] sysrq_reset_seq_param_set at ffffffff8038c030 #3 [ff2000001039bda0] __handle_sysrq at ffffffff8038c5f8 #4 [ff2000001039be00] write_sysrq_trigger at ffffffff8038cad8 #5 [ff2000001039be20] proc_reg_write at ffffffff801b7edc #6 [ff2000001039be40] vfs_write at ffffffff80152ba6 #7 [ff2000001039be80] ksys_write at ffffffff80152ece #8 [ff2000001039bed0] sys_write at ffffffff80152f46 With the patch, we can get current kernel mode PC, the output as below, [ 17.607658] CPU: 0 PID: 113 Comm: sh Kdump: loaded Not tainted 5.18.9 #42 [ 17.607937] Hardware name: riscv-virtio,qemu (DT) [ 17.608150] epc : ffffffff800078f8 ra : ffffffff8008862c sp : ff20000010333b90 [ 17.608441] gp : ffffffff810dde38 tp : ff6000000226c200 t0 : ffffffff8032be68 [ 17.608741] t1 : 0720072007200720 t2 : 666666666666663c s0 : ff20000010333cf0 [ 17.609025] s1 : 0000000000000000 a0 : ff20000010333b98 a1 : 0000000000000001 [ 17.609320] a2 : 0000000000000010 a3 : 0000000000000000 a4 : 0000000000000000 [ 17.609601] a5 : ff60000001c78000 a6 : 000000000000003c a7 : ffffffff8035c9a4 [ 17.609894] s2 : ffffffff810df0a8 s3 : ffffffff810df718 s4 : ff20000010333b98 [ 17.610186] s5 : 0000000000000000 s6 : 0000000000000007 s7 : ffffffff80c4a468 [ 17.610469] s8 : 00ffffffca281410 s9 : 0000000000000007 s10: 00aaaaaab5bb6700 [ 17.610755] s11: 0000000000000001 t3 : ff60000001218f00 t4 : ff60000001218f00 [ 17.611041] t5 : ff60000001218000 t6 : ff20000010333988 [ 17.611255] status: 0000000200000020 badaddr: 0000000000000000 cause: 0000000000000008 With the correct PC, the backtrace showed by crash tool as below, crash> bt PID: 113 TASK: ff6000000226c200 CPU: 0 COMMAND: "sh" #0 [ff20000010333b90] riscv_crash_save_regs at ffffffff800078f8 <--- Normal #1 [ff20000010333cf0] panic at ffffffff806578c6 #2 [ff20000010333d50] sysrq_reset_seq_param_set at ffffffff8038c03c #3 [ff20000010333da0] __handle_sysrq at ffffffff8038c604 #4 [ff20000010333e00] write_sysrq_trigger at ffffffff8038cae4 #5 [ff20000010333e20] proc_reg_write at ffffffff801b7ee8 #6 [ff20000010333e40] vfs_write at ffffffff80152bb2 #7 [ff20000010333e80] ksys_write at ffffffff80152eda #8 [ff20000010333ed0] sys_write at ffffffff80152f52 Fixes: e53d281 ("RISC-V: Add kdump support") Co-developed-by: Guo Ren <guoren@kernel.org> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> Link: https://lore.kernel.org/r/20220811074150.3020189-3-xianting.tian@linux.alibaba.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Previously if we couldn't find an entry in the cache and we failed to allocate memory for a new cache entry we would fail the network object label lookup; this is obviously not ideal. This patch fixes this so that we return the object label even if we can't cache the object at this point in time due to memory pressure. The GitHub issue tracker is below: * SELinuxProject/selinux-kernel#3 Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Reinazhard <reinazhard@gmail.com>

This attempts to avoid circular locking dependency between sock_lock and hdev_lock: WARNING: possible circular locking dependency detected 6.0.0-rc7-03728-g18dd8ab0a783 #3 Not tainted ------------------------------------------------------ kworker/u3:2/53 is trying to acquire lock: ffff888000254130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at: iso_conn_del+0xbd/0x1d0 but task is already holding lock: ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0x1b5/0x500 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock+0x10e/0xfe0 hci_le_remote_feat_complete_evt+0x17f/0x320 hci_event_packet+0x39c/0x7d0 hci_rx_work+0x2bf/0x950 process_one_work+0x569/0x980 worker_thread+0x2a3/0x6f0 kthread+0x153/0x180 ret_from_fork+0x22/0x30 -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock+0x10e/0xfe0 iso_connect_cis+0x6f/0x5a0 iso_sock_connect+0x1af/0x710 __sys_connect+0x17e/0x1b0 __x64_sys_connect+0x37/0x50 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x62/0xcc -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}: __lock_acquire+0x1b51/0x33d0 lock_acquire+0x16f/0x3b0 lock_sock_nested+0x32/0x80 iso_conn_del+0xbd/0x1d0 iso_connect_cfm+0x226/0x680 hci_le_cis_estabilished_evt+0x1ed/0x500 hci_event_packet+0x39c/0x7d0 hci_rx_work+0x2bf/0x950 process_one_work+0x569/0x980 worker_thread+0x2a3/0x6f0 kthread+0x153/0x180 ret_from_fork+0x22/0x30 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_ISO --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO); *** DEADLOCK *** 4 locks held by kworker/u3:2/53: #0: ffff8880021d9130 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x4ad/0x980 #1: ffff888002387de0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x4ad/0x980 #2: ffff888001ac0070 (&hdev->lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0xc3/0x500 #3: ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0x1b5/0x500 Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

We need to check if we have a OS prefix, otherwise we stumble on a metric segv that I'm now seeing in Arnaldo's tree: $ gdb --args perf stat -M Backend true ... Performance counter stats for 'true': 4,712,355 TOPDOWN.SLOTS # 17.3 % tma_core_bound Program received signal SIGSEGV, Segmentation fault. __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77 77 ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory. (gdb) bt #0 __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77 #1 0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680 <_IO_2_1_stderr_>) #2 0x0000555555779f28 in do_new_line_std (config=0x555555e077c0 <stat_config>, os=0x7fffffffbf10) at util/stat-display.c:356 #3 0x000055555577a081 in print_metric_std (config=0x555555e077c0 <stat_config>, ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f", unit=0x7fffffffbb10 "% tma_memory_bound", val=13.165355724442199) at util/stat-display.c:380 #4 0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>, metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY + EXE_ACTIVITY.BOUND_ON_STORES) / (CYCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring * EXE_ACTIVITY.2_PORTS_UTIL) + EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0, metric_refs=0x555555ec81d0, name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80 "tma_memory_bound", metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0, out=0x7fffffffbd90, st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934 #5 0x0000555555778cac in perf_stat__print_shadow_stats (config=0x555555e077c0 <stat_config>, evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90, metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:1329 #6 0x000055555577b6a0 in printout (config=0x555555e077c0 <stat_config>, os=0x7fffffffbf10, uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at util/stat-display.c:741 #7 0x000055555577bc74 in print_counter_aggrdata (config=0x555555e077c0 <stat_config>, counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838 #8 0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>, counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957 #9 0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610, config=0x555555e077c0 <stat_config>, _target=0x555555e01c80 <target>, ts=0x0, argc=1, argv=0x7fffffffe450) at util/stat-display.c:1413 #10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450) at builtin-stat.c:1040 #11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at builtin-stat.c:2665 #12 0x00005555556b1eea in run_builtin (p=0x555555e11f70 <commands+336>, argc=4, argv=0x7fffffffe450) at perf.c:322 #13 0x00005555556b2181 in handle_internal_command (argc=4, argv=0x7fffffffe450) at perf.c:376 #14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c, argv=0x7fffffffe270) at perf.c:420 #15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550 (gdb) Fixes: f123b2d ("perf stat: Remove prefix argument in print_metric_headers()") Signed-off-by: Ian Rogers <irogers@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com> Link: http://lore.kernel.org/lkml/CAP-5=fUOjSM5HajU9TCD6prY39LbX4OQbkEbtKPPGRBPBN=_VQ@mail.gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

@m

The propagate_mnt() function handles mount propagation when creating mounts and propagates the source mount tree @source_mnt to all applicable nodes of the destination propagation mount tree headed by @dest_mnt. Unfortunately it contains a bug where it fails to terminate at peers of @source_mnt when looking up copies of the source mount that become masters for copies of the source mount tree mounted on top of slaves in the destination propagation tree causing a NULL dereference. Once the mechanics of the bug are understood it's easy to trigger. Because of unprivileged user namespaces it is available to unprivileged users. While fixing this bug we've gotten confused multiple times due to unclear terminology or missing concepts. So let's start this with some clarifications: * The terms "master" or "peer" denote a shared mount. A shared mount belongs to a peer group. * A peer group is a set of shared mounts that propagate to each other. They are identified by a peer group id. The peer group id is available in @shared_mnt->mnt_group_id. Shared mounts within the same peer group have the same peer group id. The peers in a peer group can be reached via @shared_mnt->mnt_share. * The terms "slave mount" or "dependent mount" denote a mount that receives propagation from a peer in a peer group. IOW, shared mounts may have slave mounts and slave mounts have shared mounts as their master. Slave mounts of a given peer in a peer group are listed on that peers slave list available at @shared_mnt->mnt_slave_list. * The term "master mount" denotes a mount in a peer group. IOW, it denotes a shared mount or a peer mount in a peer group. The term "master mount" - or "master" for short - is mostly used when talking in the context of slave mounts that receive propagation from a master mount. A master mount of a slave identifies the closest peer group a slave mount receives propagation from. The master mount of a slave can be identified via @slave_mount->mnt_master. Different slaves may point to different masters in the same peer group. * Multiple peers in a peer group can have non-empty ->mnt_slave_lists. Non-empty ->mnt_slave_lists of peers don't intersect. Consequently, to ensure all slave mounts of a peer group are visited the ->mnt_slave_lists of all peers in a peer group have to be walked. * Slave mounts point to a peer in the closest peer group they receive propagation from via @slave_mnt->mnt_master (see above). Together with these peers they form a propagation group (see below). The closest peer group can thus be identified through the peer group id @slave_mnt->mnt_master->mnt_group_id of the peer/master that a slave mount receives propagation from. * A shared-slave mount is a slave mount to a peer group pg1 while also a peer in another peer group pg2. IOW, a peer group may receive propagation from another peer group. If a peer group pg1 is a slave to another peer group pg2 then all peers in peer group pg1 point to the same peer in peer group pg2 via ->mnt_master. IOW, all peers in peer group pg1 appear on the same ->mnt_slave_list. IOW, they cannot be slaves to different peer groups. * A pure slave mount is a slave mount that is a slave to a peer group but is not a peer in another peer group. * A propagation group denotes the set of mounts consisting of a single peer group pg1 and all slave mounts and shared-slave mounts that point to a peer in that peer group via ->mnt_master. IOW, all slave mounts such that @slave_mnt->mnt_master->mnt_group_id is equal to @shared_mnt->mnt_group_id. The concept of a propagation group makes it easier to talk about a single propagation level in a propagation tree. For example, in propagate_mnt() the immediate peers of @dest_mnt and all slaves of @dest_mnt's peer group form a propagation group propg1. So a shared-slave mount that is a slave in propg1 and that is a peer in another peer group pg2 forms another propagation group propg2 together with all slaves that point to that shared-slave mount in their ->mnt_master. * A propagation tree refers to all mounts that receive propagation starting from a specific shared mount. For example, for propagate_mnt() @dest_mnt is the start of a propagation tree. The propagation tree ecompasses all mounts that receive propagation from @dest_mnt's peer group down to the leafs. With that out of the way let's get to the actual algorithm. We know that @dest_mnt is guaranteed to be a pure shared mount or a shared-slave mount. This is guaranteed by a check in attach_recursive_mnt(). So propagate_mnt() will first propagate the source mount tree to all peers in @dest_mnt's peer group: for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) { ret = propagate_one(n); if (ret) goto out; } Notice, that the peer propagation loop of propagate_mnt() doesn't propagate @dest_mnt itself. @dest_mnt is mounted directly in attach_recursive_mnt() after we propagated to the destination propagation tree. The mount that will be mounted on top of @dest_mnt is @source_mnt. This copy was created earlier even before we entered attach_recursive_mnt() and doesn't concern us a lot here. It's just important to notice that when propagate_mnt() is called @source_mnt will not yet have been mounted on top of @dest_mnt. Thus, @source_mnt->mnt_parent will either still point to @source_mnt or - in the case @source_mnt is moved and thus already attached - still to its former parent. For each peer @m in @dest_mnt's peer group propagate_one() will create a new copy of the source mount tree and mount that copy @child on @m such that @child->mnt_parent points to @m after propagate_one() returns. propagate_one() will stash the last destination propagation node @m in @last_dest and the last copy it created for the source mount tree in @last_source. Hence, if we call into propagate_one() again for the next destination propagation node @m, @last_dest will point to the previous destination propagation node and @last_source will point to the previous copy of the source mount tree and mounted on @last_dest. Each new copy of the source mount tree is created from the previous copy of the source mount tree. This will become important later. The peer loop in propagate_mnt() is straightforward. We iterate through the peers copying and updating @last_source and @last_dest as we go through them and mount each copy of the source mount tree @child on a peer @m in @dest_mnt's peer group. After propagate_mnt() handled the peers in @dest_mnt's peer group propagate_mnt() will propagate the source mount tree down the propagation tree that @dest_mnt's peer group propagates to: for (m = next_group(dest_mnt, dest_mnt); m; m = next_group(m, dest_mnt)) { /* everything in that slave group */ n = m; do { ret = propagate_one(n); if (ret) goto out; n = next_peer(n); } while (n != m); } The next_group() helper will recursively walk the destination propagation tree, descending into each propagation group of the propagation tree. The important part is that it takes care to propagate the source mount tree to all peers in the peer group of a propagation group before it propagates to the slaves to those peers in the propagation group. IOW, it creates and mounts copies of the source mount tree that become masters before it creates and mounts copies of the source mount tree that become slaves to these masters. It is important to remember that propagating the source mount tree to each mount @m in the destination propagation tree simply means that we create and mount new copies @child of the source mount tree on @m such that @child->mnt_parent points to @m. Since we know that each node @m in the destination propagation tree headed by @dest_mnt's peer group will be overmounted with a copy of the source mount tree and since we know that the propagation properties of each copy of the source mount tree we create and mount at @m will mostly mirror the propagation properties of @m. We can use that information to create and mount the copies of the source mount tree that become masters before their slaves. The easy case is always when @m and @last_dest are peers in a peer group of a given propagation group. In that case we know that we can simply copy @last_source without having to figure out what the master for the new copy @child of the source mount tree needs to be as we've done that in a previous call to propagate_one(). The hard case is when we're dealing with a slave mount or a shared-slave mount @m in a destination propagation group that we need to create and mount a copy of the source mount tree on. For each propagation group in the destination propagation tree we propagate the source mount tree to we want to make sure that the copies @child of the source mount tree we create and mount on slaves @m pick an ealier copy of the source mount tree that we mounted on a master @m of the destination propagation group as their master. This is a mouthful but as far as we can tell that's the core of it all. But, if we keep track of the masters in the destination propagation tree @m we can use the information to find the correct master for each copy of the source mount tree we create and mount at the slaves in the destination propagation tree @m. Let's walk through the base case as that's still fairly easy to grasp. If we're dealing with the first slave in the propagation group that @dest_mnt is in then we don't yet have marked any masters in the destination propagation tree. We know the master for the first slave to @dest_mnt's peer group is simple @dest_mnt. So we expect this algorithm to yield a copy of the source mount tree that was mounted on a peer in @dest_mnt's peer group as the master for the copy of the source mount tree we want to mount at the first slave @m: for (n = m; ; n = p) { p = n->mnt_master; if (p == dest_master || IS_MNT_MARKED(p)) break; } For the first slave we walk the destination propagation tree all the way up to a peer in @dest_mnt's peer group. IOW, the propagation hierarchy can be walked by walking up the @mnt->mnt_master hierarchy of the destination propagation tree @m. We will ultimately find a peer in @dest_mnt's peer group and thus ultimately @dest_mnt->mnt_master. Btw, here the assumption we listed at the beginning becomes important. Namely, that peers in a peer group pg1 that are slaves in another peer group pg2 appear on the same ->mnt_slave_list. IOW, all slaves who are peers in peer group pg1 point to the same peer in peer group pg2 via their ->mnt_master. Otherwise the termination condition in the code above would be wrong and next_group() would be broken too. So the first iteration sets: n = m; p = n->mnt_master; such that @p now points to a peer or @dest_mnt itself. We walk up one more level since we don't have any marked mounts. So we end up with: n = dest_mnt; p = dest_mnt->mnt_master; If @dest_mnt's peer group is not slave to another peer group then @p is now NULL. If @dest_mnt's peer group is a slave to another peer group then @p now points to @dest_mnt->mnt_master points which is a master outside the propagation tree we're dealing with. Now we need to figure out the master for the copy of the source mount tree we're about to create and mount on the first slave of @dest_mnt's peer group: do { struct mount *parent = last_source->mnt_parent; if (last_source == first_source) break; done = parent->mnt_master == p; if (done && peers(n, parent)) break; last_source = last_source->mnt_master; } while (!done); We know that @last_source->mnt_parent points to @last_dest and @last_dest is the last peer in @dest_mnt's peer group we propagated to in the peer loop in propagate_mnt(). Consequently, @last_source is the last copy we created and mount on that last peer in @dest_mnt's peer group. So @last_source is the master we want to pick. We know that @last_source->mnt_parent->mnt_master points to @last_dest->mnt_master. We also know that @last_dest->mnt_master is either NULL or points to a master outside of the destination propagation tree and so does @p. Hence: done = parent->mnt_master == p; is trivially true in the base condition. We also know that for the first slave mount of @dest_mnt's peer group that @last_dest either points @dest_mnt itself because it was initialized to: last_dest = dest_mnt; at the beginning of propagate_mnt() or it will point to a peer of @dest_mnt in its peer group. In both cases it is guaranteed that on the first iteration @n and @parent are peers (Please note the check for peers here as that's important.): if (done && peers(n, parent)) break; So, as we expected, we select @last_source, which referes to the last copy of the source mount tree we mounted on the last peer in @dest_mnt's peer group, as the master of the first slave in @dest_mnt's peer group. The rest is taken care of by clone_mnt(last_source, ...). We'll skip over that part otherwise this becomes a blogpost. At the end of propagate_mnt() we now mark @m->mnt_master as the first master in the destination propagation tree that is distinct from @dest_mnt->mnt_master. IOW, we mark @dest_mnt itself as a master. By marking @dest_mnt or one of it's peers we are able to easily find it again when we later lookup masters for other copies of the source mount tree we mount copies of the source mount tree on slaves @m to @dest_mnt's peer group. This, in turn allows us to find the master we selected for the copies of the source mount tree we mounted on master in the destination propagation tree again. The important part is to realize that the code makes use of the fact that the last copy of the source mount tree stashed in @last_source was mounted on top of the previous destination propagation node @last_dest. What this means is that @last_source allows us to walk the destination propagation hierarchy the same way each destination propagation node @m does. If we take @last_source, which is the copy of @source_mnt we have mounted on @last_dest in the previous iteration of propagate_one(), then we know @last_source->mnt_parent points to @last_dest but we also know that as we walk through the destination propagation tree that @last_source->mnt_master will point to an earlier copy of the source mount tree we mounted one an earlier destination propagation node @m. IOW, @last_source->mnt_parent will be our hook into the destination propagation tree and each consecutive @last_source->mnt_master will lead us to an earlier propagation node @m via @last_source->mnt_master->mnt_parent. Hence, by walking up @last_source->mnt_master, each of which is mounted on a node that is a master @m in the destination propagation tree we can also walk up the destination propagation hierarchy. So, for each new destination propagation node @m we use the previous copy of @last_source and the fact it's mounted on the previous propagation node @last_dest via @last_source->mnt_master->mnt_parent to determine what the master of the new copy of @last_source needs to be. The goal is to find the _closest_ master that the new copy of the source mount tree we are about to create and mount on a slave @m in the destination propagation tree needs to pick. IOW, we want to find a suitable master in the propagation group. As the propagation structure of the source mount propagation tree we create mirrors the propagation structure of the destination propagation tree we can find @m's closest master - i.e., a marked master - which is a peer in the closest peer group that @m receives propagation from. We store that closest master of @m in @p as before and record the slave to that master in @n We then search for this master @p via @last_source by walking up the master hierarchy starting from the last copy of the source mount tree stored in @last_source that we created and mounted on the previous destination propagation node @m. We will try to find the master by walking @last_source->mnt_master and by comparing @last_source->mnt_master->mnt_parent->mnt_master to @p. If we find @p then we can figure out what earlier copy of the source mount tree needs to be the master for the new copy of the source mount tree we're about to create and mount at the current destination propagation node @m. If @last_source->mnt_master->mnt_parent and @n are peers then we know that the closest master they receive propagation from is @last_source->mnt_master->mnt_parent->mnt_master. If not then the closest immediate peer group that they receive propagation from must be one level higher up. This builds on the earlier clarification at the beginning that all peers in a peer group which are slaves of other peer groups all point to the same ->mnt_master, i.e., appear on the same ->mnt_slave_list, of the closest peer group that they receive propagation from. However, terminating the walk has corner cases. If the closest marked master for a given destination node @m cannot be found by walking up the master hierarchy via @last_source->mnt_master then we need to terminate the walk when we encounter @source_mnt again. This isn't an arbitrary termination. It simply means that the new copy of the source mount tree we're about to create has a copy of the source mount tree we created and mounted on a peer in @dest_mnt's peer group as its master. IOW, @source_mnt is the peer in the closest peer group that the new copy of the source mount tree receives propagation from. We absolutely have to stop @source_mnt because @last_source->mnt_master either points outside the propagation hierarchy we're dealing with or it is NULL because @source_mnt isn't a shared-slave. So continuing the walk past @source_mnt would cause a NULL dereference via @last_source->mnt_master->mnt_parent. And so we have to stop the walk when we encounter @source_mnt again. One scenario where this can happen is when we first handled a series of slaves of @dest_mnt's peer group and then encounter peers in a new peer group that is a slave to @dest_mnt's peer group. We handle them and then we encounter another slave mount to @dest_mnt that is a pure slave to @dest_mnt's peer group. That pure slave will have a peer in @dest_mnt's peer group as its master. Consequently, the new copy of the source mount tree will need to have @source_mnt as it's master. So we walk the propagation hierarchy all the way up to @source_mnt based on @last_source->mnt_master. So terminate on @source_mnt, easy peasy. Except, that the check misses something that the rest of the algorithm already handles. If @dest_mnt has peers in it's peer group the peer loop in propagate_mnt(): for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) { ret = propagate_one(n); if (ret) goto out; } will consecutively update @last_source with each previous copy of the source mount tree we created and mounted at the previous peer in @dest_mnt's peer group. So after that loop terminates @last_source will point to whatever copy of the source mount tree was created and mounted on the last peer in @dest_mnt's peer group. Furthermore, if there is even a single additional peer in @dest_mnt's peer group then @last_source will __not__ point to @source_mnt anymore. Because, as we mentioned above, @dest_mnt isn't even handled in this loop but directly in attach_recursive_mnt(). So it can't even accidently come last in that peer loop. So the first time we handle a slave mount @m of @dest_mnt's peer group the copy of the source mount tree we create will make the __last copy of the source mount tree we created and mounted on the last peer in @dest_mnt's peer group the master of the new copy of the source mount tree we create and mount on the first slave of @dest_mnt's peer group__. But this means that the termination condition that checks for @source_mnt is wrong. The @source_mnt cannot be found anymore by propagate_one(). Instead it will find the last copy of the source mount tree we created and mounted for the last peer of @dest_mnt's peer group again. And that is a peer of @source_mnt not @source_mnt itself. IOW, we fail to terminate the loop correctly and ultimately dereference @last_source->mnt_master->mnt_parent. When @source_mnt's peer group isn't slave to another peer group then @last_source->mnt_master is NULL causing the splat below. For example, assume @dest_mnt is a pure shared mount and has three peers in its peer group: =================================================================================== mount-id mount-parent-id peer-group-id =================================================================================== (@dest_mnt) mnt_master[216] 309 297 shared:216 \ (@source_mnt) mnt_master[218]: 609 609 shared:218 (1) mnt_master[216]: 607 605 shared:216 \ (P1) mnt_master[218]: 624 607 shared:218 (2) mnt_master[216]: 576 574 shared:216 \ (P2) mnt_master[218]: 625 576 shared:218 (3) mnt_master[216]: 545 543 shared:216 \ (P3) mnt_master[218]: 626 545 shared:218 After this sequence has been processed @last_source will point to (P3), the copy generated for the third peer in @dest_mnt's peer group we handled. So the copy of the source mount tree (P4) we create and mount on the first slave of @dest_mnt's peer group: =================================================================================== mount-id mount-parent-id peer-group-id =================================================================================== mnt_master[216] 309 297 shared:216 / / (S0) mnt_slave 483 481 master:216 \ \ (P3) mnt_master[218] 626 545 shared:218 \ / \/ (P4) mnt_slave 627 483 master:218 will pick the last copy of the source mount tree (P3) as master, not (S0). When walking the propagation hierarchy via @last_source's master hierarchy we encounter (P3) but not (S0), i.e., @source_mnt. We can fix this in multiple ways: (1) By setting @last_source to @source_mnt after we processed the peers in @dest_mnt's peer group right after the peer loop in propagate_mnt(). (2) By changing the termination condition that relies on finding exactly @source_mnt to finding a peer of @source_mnt. (3) By only moving @last_source when we actually venture into a new peer group or some clever variant thereof. The first two options are minimally invasive and what we want as a fix. The third option is more intrusive but something we'd like to explore in the near future. This passes all LTP tests and specifically the mount propagation testsuite part of it. It also holds up against all known reproducers of this issues. Final words. First, this is a clever but __worringly__ underdocumented algorithm. There isn't a single detailed comment to be found in next_group(), propagate_one() or anywhere else in that file for that matter. This has been a giant pain to understand and work through and a bug like this is insanely difficult to fix without a detailed understanding of what's happening. Let's not talk about the amount of time that was sunk into fixing this. Second, all the cool kids with access to unshare --mount --user --map-root --propagation=unchanged are going to have a lot of fun. IOW, triggerable by unprivileged users while namespace_lock() lock is held. [ 115.848393] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 115.848967] #PF: supervisor read access in kernel mode [ 115.849386] #PF: error_code(0x0000) - not-present page [ 115.849803] PGD 0 P4D 0 [ 115.850012] Oops: 0000 [#1] PREEMPT SMP PTI [ 115.850354] CPU: 0 PID: 15591 Comm: mount Not tainted 6.1.0-rc7 #3 [ 115.850851] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 115.851510] RIP: 0010:propagate_one.part.0+0x7f/0x1a0 [ 115.851924] Code: 75 eb 4c 8b 05 c2 25 37 02 4c 89 ca 48 8b 4a 10 49 39 d0 74 1e 48 3b 81 e0 00 00 00 74 26 48 8b 92 e0 00 00 00 be 01 00 00 00 <48> 8b 4a 10 49 39 d0 75 e2 40 84 f6 74 38 4c 89 05 84 25 37 02 4d [ 115.853441] RSP: 0018:ffffb8d5443d7d50 EFLAGS: 00010282 [ 115.853865] RAX: ffff8e4d87c41c80 RBX: ffff8e4d88ded780 RCX: ffff8e4da4333a00 [ 115.854458] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8e4d88ded780 [ 115.855044] RBP: ffff8e4d88ded780 R08: ffff8e4da4338000 R09: ffff8e4da43388c0 [ 115.855693] R10: 0000000000000002 R11: ffffb8d540158000 R12: ffffb8d5443d7da8 [ 115.856304] R13: ffff8e4d88ded780 R14: 0000000000000000 R15: 0000000000000000 [ 115.856859] FS: 00007f92c90c9800(0000) GS:ffff8e4dfdc00000(0000) knlGS:0000000000000000 [ 115.857531] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 115.858006] CR2: 0000000000000010 CR3: 0000000022f4c002 CR4: 00000000000706f0 [ 115.858598] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 115.859393] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 115.860099] Call Trace: [ 115.860358] <TASK> [ 115.860535] propagate_mnt+0x14d/0x190 [ 115.860848] attach_recursive_mnt+0x274/0x3e0 [ 115.861212] path_mount+0x8c8/0xa60 [ 115.861503] __x64_sys_mount+0xf6/0x140 [ 115.861819] do_syscall_64+0x5b/0x80 [ 115.862117] ? do_faccessat+0x123/0x250 [ 115.862435] ? syscall_exit_to_user_mode+0x17/0x40 [ 115.862826] ? do_syscall_64+0x67/0x80 [ 115.863133] ? syscall_exit_to_user_mode+0x17/0x40 [ 115.863527] ? do_syscall_64+0x67/0x80 [ 115.863835] ? do_syscall_64+0x67/0x80 [ 115.864144] ? do_syscall_64+0x67/0x80 [ 115.864452] ? exc_page_fault+0x70/0x170 [ 115.864775] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 115.865187] RIP: 0033:0x7f92c92b0ebe [ 115.865480] Code: 48 8b 0d 75 4f 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 42 4f 0c 00 f7 d8 64 89 01 48 [ 115.866984] RSP: 002b:00007fff000aa728 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 [ 115.867607] RAX: ffffffffffffffda RBX: 000055a77888d6b0 RCX: 00007f92c92b0ebe [ 115.868240] RDX: 000055a77888d8e0 RSI: 000055a77888e6e0 RDI: 000055a77888e620 [ 115.868823] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 115.869403] R10: 0000000000001000 R11: 0000000000000246 R12: 000055a77888e620 [ 115.869994] R13: 000055a77888d8e0 R14: 00000000ffffffff R15: 00007f92c93e4076 [ 115.870581] </TASK> [ 115.870763] Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set rfkill nf_tables nfnetlink qrtr snd_intel8x0 sunrpc snd_ac97_codec ac97_bus snd_pcm snd_timer intel_rapl_msr intel_rapl_common snd vboxguest intel_powerclamp video rapl joydev soundcore i2c_piix4 wmi fuse zram xfs vmwgfx crct10dif_pclmul crc32_pclmul crc32c_intel polyval_clmulni polyval_generic drm_ttm_helper ttm e1000 ghash_clmulni_intel serio_raw ata_generic pata_acpi scsi_dh_rdac scsi_dh_emc scsi_dh_alua dm_multipath [ 115.875288] CR2: 0000000000000010 [ 115.875641] ---[ end trace 0000000000000000 ]--- [ 115.876135] RIP: 0010:propagate_one.part.0+0x7f/0x1a0 [ 115.876551] Code: 75 eb 4c 8b 05 c2 25 37 02 4c 89 ca 48 8b 4a 10 49 39 d0 74 1e 48 3b 81 e0 00 00 00 74 26 48 8b 92 e0 00 00 00 be 01 00 00 00 <48> 8b 4a 10 49 39 d0 75 e2 40 84 f6 74 38 4c 89 05 84 25 37 02 4d [ 115.878086] RSP: 0018:ffffb8d5443d7d50 EFLAGS: 00010282 [ 115.878511] RAX: ffff8e4d87c41c80 RBX: ffff8e4d88ded780 RCX: ffff8e4da4333a00 [ 115.879128] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8e4d88ded780 [ 115.879715] RBP: ffff8e4d88ded780 R08: ffff8e4da4338000 R09: ffff8e4da43388c0 [ 115.880359] R10: 0000000000000002 R11: ffffb8d540158000 R12: ffffb8d5443d7da8 [ 115.880962] R13: ffff8e4d88ded780 R14: 0000000000000000 R15: 0000000000000000 [ 115.881548] FS: 00007f92c90c9800(0000) GS:ffff8e4dfdc00000(0000) knlGS:0000000000000000 [ 115.882234] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 115.882713] CR2: 0000000000000010 CR3: 0000000022f4c002 CR4: 00000000000706f0 [ 115.883314] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 115.883966] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fixes: f2ebb3a ("smarter propagate_mnt()") Fixes: 5ec0811 ("propogate_mnt: Handle the first propogated copy being a slave") Cc: <stable@vger.kernel.org> Reported-by: Ditang Chen <ditang.c@gmail.com> Signed-off-by: Seth Forshee (Digital Ocean) <sforshee@kernel.org> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> --- If there are no big objections I'll get this to Linus rather sooner than later.

When doing timestamping in lan966x and having PROVE_LOCKING enabled the following warning is shown. ======================================================== WARNING: possible irq lock inversion dependency detected 6.2.0-rc7-01749-gc54e1f7f7e36 #2786 Tainted: G N -------------------------------------------------------- swapper/0/0 just changed the state of lock: c2609f50 (_xmit_ETHER#2){+.-.}-{2:2}, at: sch_direct_xmit+0x16c/0x2e8 but this lock took another, SOFTIRQ-unsafe lock in the past: (&lan966x->ptp_ts_id_lock){+.+.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lan966x->ptp_ts_id_lock); local_irq_disable(); lock(_xmit_ETHER#2); lock(&lan966x->ptp_ts_id_lock); <Interrupt> lock(_xmit_ETHER#2); *** DEADLOCK *** 5 locks held by swapper/0/0: #0: c1001e18 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0x0/0x33c #1: c105e7c4 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x134/0x81c #2: c105e7d8 (rcu_read_lock_bh){....}-{1:2}, at: ip6_finish_output2+0x17c/0xc64 #3: c105e7d8 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x4c/0x1224 #4: c3056174 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x354/0x1224 the shortest dependencies between 2nd lock and 1st lock: -> (&lan966x->ptp_ts_id_lock){+.+.}-{2:2} { HARDIRQ-ON-W at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 lan966x_ptp_irq_handler+0x164/0x2a8 irq_thread_fn+0x1c/0x78 irq_thread+0x130/0x278 kthread+0xec/0x110 ret_from_fork+0x14/0x28 SOFTIRQ-ON-W at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 lan966x_ptp_irq_handler+0x164/0x2a8 irq_thread_fn+0x1c/0x78 irq_thread+0x130/0x278 kthread+0xec/0x110 ret_from_fork+0x14/0x28 INITIAL USE at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock_irqsave+0x4c/0x68 lan966x_ptp_txtstamp_request+0x128/0x1cc lan966x_port_xmit+0x224/0x43c dev_hard_start_xmit+0xa8/0x2f0 sch_direct_xmit+0x108/0x2e8 __dev_queue_xmit+0x41c/0x1224 packet_sendmsg+0xdb4/0x134c __sys_sendto+0xd0/0x154 sys_send+0x18/0x20 ret_fast_syscall+0x0/0x1c } ... key at: [<c174ba0c>] __key.2+0x0/0x8 ... acquired at: _raw_spin_lock_irqsave+0x4c/0x68 lan966x_ptp_txtstamp_request+0x128/0x1cc lan966x_port_xmit+0x224/0x43c dev_hard_start_xmit+0xa8/0x2f0 sch_direct_xmit+0x108/0x2e8 __dev_queue_xmit+0x41c/0x1224 packet_sendmsg+0xdb4/0x134c __sys_sendto+0xd0/0x154 sys_send+0x18/0x20 ret_fast_syscall+0x0/0x1c -> (_xmit_ETHER#2){+.-.}-{2:2} { HARDIRQ-ON-W at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 netif_freeze_queues+0x38/0x68 dev_deactivate_many+0xac/0x388 dev_deactivate+0x38/0x6c linkwatch_do_dev+0x70/0x8c __linkwatch_run_queue+0xd4/0x1e8 linkwatch_event+0x24/0x34 process_one_work+0x284/0x744 worker_thread+0x28/0x4bc kthread+0xec/0x110 ret_from_fork+0x14/0x28 IN-SOFTIRQ-W at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 sch_direct_xmit+0x16c/0x2e8 __dev_queue_xmit+0x41c/0x1224 ip6_finish_output2+0x5f4/0xc64 ndisc_send_skb+0x4cc/0x81c addrconf_rs_timer+0xb0/0x2f8 call_timer_fn+0xb4/0x33c expire_timers+0xb4/0x10c run_timer_softirq+0xf8/0x2a8 __do_softirq+0xd4/0x5fc __irq_exit_rcu+0x138/0x17c irq_exit+0x8/0x28 __irq_svc+0x90/0xbc arch_cpu_idle+0x30/0x3c default_idle_call+0x44/0xac do_idle+0xc8/0x138 cpu_startup_entry+0x18/0x1c rest_init+0xcc/0x168 arch_post_acpi_subsys_init+0x0/0x8 INITIAL USE at: lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 netif_freeze_queues+0x38/0x68 dev_deactivate_many+0xac/0x388 dev_deactivate+0x38/0x6c linkwatch_do_dev+0x70/0x8c __linkwatch_run_queue+0xd4/0x1e8 linkwatch_event+0x24/0x34 process_one_work+0x284/0x744 worker_thread+0x28/0x4bc kthread+0xec/0x110 ret_from_fork+0x14/0x28 } ... key at: [<c175974c>] netdev_xmit_lock_key+0x8/0x1c8 ... acquired at: __lock_acquire+0x978/0x2978 lock_acquire.part.0+0xb0/0x248 _raw_spin_lock+0x38/0x48 sch_direct_xmit+0x16c/0x2e8 __dev_queue_xmit+0x41c/0x1224 ip6_finish_output2+0x5f4/0xc64 ndisc_send_skb+0x4cc/0x81c addrconf_rs_timer+0xb0/0x2f8 call_timer_fn+0xb4/0x33c expire_timers+0xb4/0x10c run_timer_softirq+0xf8/0x2a8 __do_softirq+0xd4/0x5fc __irq_exit_rcu+0x138/0x17c irq_exit+0x8/0x28 __irq_svc+0x90/0xbc arch_cpu_idle+0x30/0x3c default_idle_call+0x44/0xac do_idle+0xc8/0x138 cpu_startup_entry+0x18/0x1c rest_init+0xcc/0x168 arch_post_acpi_subsys_init+0x0/0x8 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G N 6.2.0-rc7-01749-gc54e1f7f7e36 #2786 Hardware name: Generic DT based system unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x58/0x70 dump_stack_lvl from mark_lock.part.0+0x59c/0x93c mark_lock.part.0 from __lock_acquire+0x978/0x2978 __lock_acquire from lock_acquire.part.0+0xb0/0x248 lock_acquire.part.0 from _raw_spin_lock+0x38/0x48 _raw_spin_lock from sch_direct_xmit+0x16c/0x2e8 sch_direct_xmit from __dev_queue_xmit+0x41c/0x1224 __dev_queue_xmit from ip6_finish_output2+0x5f4/0xc64 ip6_finish_output2 from ndisc_send_skb+0x4cc/0x81c ndisc_send_skb from addrconf_rs_timer+0xb0/0x2f8 addrconf_rs_timer from call_timer_fn+0xb4/0x33c call_timer_fn from expire_timers+0xb4/0x10c expire_timers from run_timer_softirq+0xf8/0x2a8 run_timer_softirq from __do_softirq+0xd4/0x5fc __do_softirq from __irq_exit_rcu+0x138/0x17c __irq_exit_rcu from irq_exit+0x8/0x28 irq_exit from __irq_svc+0x90/0xbc Exception stack(0xc1001f20 to 0xc1001f68) 1f20: ffffffff ffffffff 00000001 c011f840 c100e000 c100e000 c1009314 c1009370 1f40: c10f0c1a c0d5e564 c0f5da8c 00000000 00000000 c1001f70 c010f0bc c010f0c0 1f60: 600f0013 ffffffff __irq_svc from arch_cpu_idle+0x30/0x3c arch_cpu_idle from default_idle_call+0x44/0xac default_idle_call from do_idle+0xc8/0x138 do_idle from cpu_startup_entry+0x18/0x1c cpu_startup_entry from rest_init+0xcc/0x168 rest_init from arch_post_acpi_subsys_init+0x0/0x8 Fix this by using spin_lock_irqsave/spin_lock_irqrestore also inside lan966x_ptp_irq_handler. Fixes: e85a96e ("net: lan966x: Add support for ptp interrupts") Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Link: https://lore.kernel.org/r/20230217210917.2649365-1-horatiu.vultur@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

code path: ocfs2_ioctl_move_extents ocfs2_move_extents ocfs2_defrag_extent __ocfs2_move_extent + ocfs2_journal_access_di + ocfs2_split_extent //sub-paths call jbd2_journal_restart + ocfs2_journal_dirty //crash by jbs2 ASSERT crash stacks: PID: 11297 TASK: ffff974a676dcd00 CPU: 67 COMMAND: "defragfs.ocfs2" #0 [ffffb25d8dad3900] machine_kexec at ffffffff8386fe01 #1 [ffffb25d8dad3958] __crash_kexec at ffffffff8395959d #2 [ffffb25d8dad3a20] crash_kexec at ffffffff8395a45d #3 [ffffb25d8dad3a38] oops_end at ffffffff83836d3f #4 [ffffb25d8dad3a58] do_trap at ffffffff83833205 #5 [ffffb25d8dad3aa0] do_invalid_op at ffffffff83833aa6 #6 [ffffb25d8dad3ac0] invalid_op at ffffffff84200d18 [exception RIP: jbd2_journal_dirty_metadata+0x2ba] RIP: ffffffffc09ca54a RSP: ffffb25d8dad3b70 RFLAGS: 00010207 RAX: 0000000000000000 RBX: ffff9706eedc5248 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff97337029ea28 RDI: ffff9706eedc5250 RBP: ffff9703c3520200 R8: 000000000f46b0b2 R9: 0000000000000000 R10: 0000000000000001 R11: 00000001000000fe R12: ffff97337029ea28 R13: 0000000000000000 R14: ffff9703de59bf60 R15: ffff9706eedc5250 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #7 [ffffb25d8dad3ba8] ocfs2_journal_dirty at ffffffffc137fb95 [ocfs2] #8 [ffffb25d8dad3be8] __ocfs2_move_extent at ffffffffc139a950 [ocfs2] #9 [ffffb25d8dad3c80] ocfs2_defrag_extent at ffffffffc139b2d2 [ocfs2] Analysis This bug has the same root cause of 'commit 7f27ec9 ("ocfs2: call ocfs2_journal_access_di() before ocfs2_journal_dirty() in ocfs2_write_end_nolock()")'. For this bug, jbd2_journal_restart() is called by ocfs2_split_extent() during defragmenting. How to fix For ocfs2_split_extent() can handle journal operations totally by itself. Caller doesn't need to call journal access/dirty pair, and caller only needs to call journal start/stop pair. The fix method is to remove journal access/dirty from __ocfs2_move_extent(). The discussion for this patch: https://oss.oracle.com/pipermail/ocfs2-devel/2023-February/000647.html Link: https://lkml.kernel.org/r/20230217003717.32469-1-heming.zhao@suse.com Signed-off-by: Heming Zhao <heming.zhao@suse.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Sai Krishna says: ==================== octeontx2: Miscellaneous fixes This patchset includes following fixes. Patch #1 Fix for the race condition while updating APR table Patch #2 Fix end bit position in NPC scan config Patch #3 Fix depth of CAM, MEM table entries Patch #4 Fix in increase the size of DMAC filter flows Patch #5 Fix driver crash resulting from invalid interface type information retrieved from firmware Patch #6 Fix incorrect mask used while installing filters involving fragmented packets Patch #7 Fixes for NPC field hash extract w.r.t IPV6 hash reduction, IPV6 filed hash configuration. Patch #8 Fix for NPC hardware parser configuration destination address hash, IPV6 endianness issues. Patch #9 Fix for skipping mbox initialization for PFs disabled by firmware. Patch #10 Fix disabling packet I/O in case of mailbox timeout. Patch #11 Fix detaching LF resources in case of VF probe fail. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>

…linux/kernel/git/tip/tip Pull SMP updates from Thomas Gleixner: "A large update for SMP management: - Parallel CPU bringup The reason why people are interested in parallel bringup is to shorten the (kexec) reboot time of cloud servers to reduce the downtime of the VM tenants. The current fully serialized bringup does the following per AP: 1) Prepare callbacks (allocate, intialize, create threads) 2) Kick the AP alive (e.g. INIT/SIPI on x86) 3) Wait for the AP to report alive state 4) Let the AP continue through the atomic bringup 5) Let the AP run the threaded bringup to full online state There are two significant delays: #3 The time for an AP to report alive state in start_secondary() on x86 has been measured in the range between 350us and 3.5ms depending on vendor and CPU type, BIOS microcode size etc. #4 The atomic bringup does the microcode update. This has been measured to take up to ~8ms on the primary threads depending on the microcode patch size to apply. On a two socket SKL server with 56 cores (112 threads) the boot CPU spends on current mainline about 800ms busy waiting for the APs to come up and apply microcode. That's more than 80% of the actual onlining procedure. This can be reduced significantly by splitting the bringup mechanism into two parts: 1) Run the prepare callbacks and kick the AP alive for each AP which needs to be brought up. The APs wake up, do their firmware initialization and run the low level kernel startup code including microcode loading in parallel up to the first synchronization point. (#1 and #2 above) 2) Run the rest of the bringup code strictly serialized per CPU (#3 - #5 above) as it's done today. Parallelizing that stage of the CPU bringup might be possible in theory, but it's questionable whether required surgery would be justified for a pretty small gain. If the system is large enough the first AP is already waiting at the first synchronization point when the boot CPU finished the wake-up of the last AP. That reduces the AP bringup time on that SKL from ~800ms to ~80ms, i.e. by a factor ~10x. The actual gain varies wildly depending on the system, CPU, microcode patch size and other factors. There are some opportunities to reduce the overhead further, but that needs some deep surgery in the x86 CPU bringup code. For now this is only enabled on x86, but the core functionality obviously works for all SMP capable architectures. - Enhancements for SMP function call tracing so it is possible to locate the scheduling and the actual execution points. That allows to measure IPI delivery time precisely" * tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) trace,smp: Add tracepoints for scheduling remotelly called functions trace,smp: Add tracepoints around remotelly called functions MAINTAINERS: Add CPU HOTPLUG entry x86/smpboot: Fix the parallel bringup decision x86/realmode: Make stack lock work in trampoline_compat() x86/smp: Initialize cpu_primary_thread_mask late cpu/hotplug: Fix off by one in cpuhp_bringup_mask() x86/apic: Fix use of X{,2}APIC_ENABLE in asm with older binutils x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it x86/smpboot: Support parallel startup of secondary CPUs x86/smpboot: Implement a bit spinlock to protect the realmode stack x86/apic: Save the APIC virtual base address cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE x86/apic: Provide cpu_primary_thread mask x86/smpboot: Enable split CPU startup cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism cpu/hotplug: Reset task stack state in _cpu_up() cpu/hotplug: Remove unused state functions riscv: Switch to hotplug core state synchronization parisc: Switch to hotplug core state synchronization ...

Previously if we couldn't find an entry in the cache and we failed to allocate memory for a new cache entry we would fail the network object label lookup; this is obviously not ideal. This patch fixes this so that we return the object label even if we can't cache the object at this point in time due to memory pressure. The GitHub issue tracker is below: * SELinuxProject/selinux-kernel#3 Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Reinazhard <reinazhard@gmail.com> Signed-off-by: meydiwahendra <meydiwahendra@gmail.com>

…git/vgupta/arc Pull ARC updates from Vineet Gupta: - fixes for -Wmissing-prototype warnings - missing compiler barrier in relaxed atomics - some uaccess simplification, declutter - removal of massive glocal struct cpuinfo_arc from bootlog code - __switch_to consolidation (removal of inline asm variant) - use GP to cache task pointer (vs. r25) - misc rework of entry code * tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (24 commits) ARC: boot log: fix warning arc: Explicitly include correct DT includes ARC: pt_regs: create seperate type for ecr ARCv2: entry: rearrange pt_regs slightly ARC: entry: replace 8 byte ADD.ne with 4 byte ADD2.ne ARC: entry: replace 8 byte OR with 4 byte BSET ARC: entry: Add more common chores to EXCEPTION_PROLOGUE ARC: entry: EV_MachineCheck dont re-read ECR ARC: entry: ARcompact EV_ProtV to use r10 directly ARC: entry: rework (non-functional) ARC: __switch_to: move ksp to thread_info from thread_struct ARC: __switch_to: asm with dwarf ops (vs. inline asm) ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp ARC: entry: use gp to cache task pointer (vs. r25) ARC: boot log: eliminate struct cpuinfo_arc #4: boot log per ISA ARC: boot log: eliminate struct cpuinfo_arc #3: don't export ARC: boot log: eliminate struct cpuinfo_arc #2: cache ARC: boot log: eliminate struct cpuinfo_arc #1: mm ARCv2: memset: don't prefetch for len == 0 which happens a alot ARC: uaccess: elide unaliged handling if hardware supports ...

Chuyi Zhou says: ==================== Relax allowlist for open-coded css_task iter Hi, The patchset aims to relax the allowlist for open-coded css_task iter suggested by Alexei[1]. Please see individual patches for more details. And comments are always welcome. Patch summary: * Patch #1: Relax the allowlist and let css_task iter can be used in bpf iters and any sleepable progs. * Patch #2: Add a test in cgroup_iters.c which demonstrates how css_task iters can be combined with cgroup iter. * Patch #3: Add a test to prove css_task iter can be used in normal * sleepable progs. link[1]:https://lore.kernel.org/lkml/CAADnVQKafk_junRyE=-FVAik4hjTRDtThymYGEL8hGTuYoOGpA@mail.gmail.com/ --- Changes in v2: * Fix the incorrect logic in check_css_task_iter_allowlist. Use expected_attach_type to check whether we are using bpf_iters. * Link to v1:https://lore.kernel.org/bpf/20231022154527.229117-1-zhouchuyi@bytedance.com/T/#m946f9cde86b44a13265d9a44c5738a711eb578fd Changes in v3: * Add a testcase to prove css_task can be used in fentry.s * Link to v2:https://lore.kernel.org/bpf/20231024024240.42790-1-zhouchuyi@bytedance.com/T/#m14a97041ff56c2df21bc0149449abd275b73f6a3 Changes in v4: * Add Yonghong's ack for patch #1 and patch #2. * Solve Yonghong's comments for patch #2 * Move prog 'iter_css_task_for_each_sleep' from iters_task_failure.c to iters_css_task.c. Use RUN_TESTS to prove we can load this prog. * Link to v3:https://lore.kernel.org/bpf/20231025075914.30979-1-zhouchuyi@bytedance.com/T/#m3200d8ad29af4ffab97588e297361d0a45d7585d --- ==================== Link: https://lore.kernel.org/r/20231031050438.93297-1-zhouchuyi@bytedance.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>

When LAN9303 is MDIO-connected two callchains exist into mdio->bus->write(): 1. switch ports 1&2 ("physical" PHYs): virtual (switch-internal) MDIO bus (lan9303_switch_ops->phy_{read|write})-> lan9303_mdio_phy_{read|write} -> mdiobus_{read|write}_nested 2. LAN9303 virtual PHY: virtual MDIO bus (lan9303_phy_{read|write}) -> lan9303_virt_phy_reg_{read|write} -> regmap -> lan9303_mdio_{read|write} If the latter functions just take mutex_lock(&sw_dev->device->bus->mdio_lock) it triggers a LOCKDEP false-positive splat. It's false-positive because the first mdio_lock in the second callchain above belongs to virtual MDIO bus, the second mdio_lock belongs to physical MDIO bus. Consequent annotation in lan9303_mdio_{read|write} as nested lock (similar to lan9303_mdio_phy_{read|write}, it's the same physical MDIO bus) prevents the following splat: WARNING: possible circular locking dependency detected 5.15.71 #1 Not tainted ------------------------------------------------------ kworker/u4:3/609 is trying to acquire lock: ffff000011531c68 (lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock){+.+.}-{3:3}, at: regmap_lock_mutex but task is already holding lock: ffff0000114c44d8 (&bus->mdio_lock){+.+.}-{3:3}, at: mdiobus_read which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&bus->mdio_lock){+.+.}-{3:3}: lock_acquire __mutex_lock mutex_lock_nested lan9303_mdio_read _regmap_read regmap_read lan9303_probe lan9303_mdio_probe mdio_probe really_probe __driver_probe_device driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork -> #0 (lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock){+.+.}-{3:3}: __lock_acquire lock_acquire.part.0 lock_acquire __mutex_lock mutex_lock_nested regmap_lock_mutex regmap_read lan9303_phy_read dsa_slave_phy_read __mdiobus_read mdiobus_read get_phy_device mdiobus_scan __mdiobus_register dsa_register_switch lan9303_probe lan9303_mdio_probe mdio_probe really_probe __driver_probe_device driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&bus->mdio_lock); lock(lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock); lock(&bus->mdio_lock); lock(lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock); *** DEADLOCK *** 5 locks held by kworker/u4:3/609: #0: ffff000002842938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work #1: ffff80000bacbd60 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work #2: ffff000007645178 (&dev->mutex){....}-{3:3}, at: __device_attach #3: ffff8000096e6e78 (dsa2_mutex){+.+.}-{3:3}, at: dsa_register_switch #4: ffff0000114c44d8 (&bus->mdio_lock){+.+.}-{3:3}, at: mdiobus_read stack backtrace: CPU: 1 PID: 609 Comm: kworker/u4:3 Not tainted 5.15.71 #1 Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace show_stack dump_stack_lvl dump_stack print_circular_bug check_noncircular __lock_acquire lock_acquire.part.0 lock_acquire __mutex_lock mutex_lock_nested regmap_lock_mutex regmap_read lan9303_phy_read dsa_slave_phy_read __mdiobus_read mdiobus_read get_phy_device mdiobus_scan __mdiobus_register dsa_register_switch lan9303_probe lan9303_mdio_probe ... Cc: stable@vger.kernel.org Fixes: dc70058 ("net: dsa: LAN9303: add MDIO managed mode support") Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20231027065741.534971-1-alexander.sverdlin@siemens.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>

KMSAN reported the following uninit-value access issue: ===================================================== BUG: KMSAN: uninit-value in virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421 virtio_transport_recv_pkt+0x1dfb/0x26a0 net/vmw_vsock/virtio_transport_common.c:1421 vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 kthread+0x3cc/0x520 kernel/kthread.c:388 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Uninit was stored to memory at: virtio_transport_space_update net/vmw_vsock/virtio_transport_common.c:1274 [inline] virtio_transport_recv_pkt+0x1ee8/0x26a0 net/vmw_vsock/virtio_transport_common.c:1415 vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 kthread+0x3cc/0x520 kernel/kthread.c:388 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Uninit was created at: slab_post_alloc_hook+0x105/0xad0 mm/slab.h:767 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5a2/0xaf0 mm/slub.c:3523 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:559 __alloc_skb+0x2fd/0x770 net/core/skbuff.c:650 alloc_skb include/linux/skbuff.h:1286 [inline] virtio_vsock_alloc_skb include/linux/virtio_vsock.h:66 [inline] virtio_transport_alloc_skb+0x90/0x11e0 net/vmw_vsock/virtio_transport_common.c:58 virtio_transport_reset_no_sock net/vmw_vsock/virtio_transport_common.c:957 [inline] virtio_transport_recv_pkt+0x1279/0x26a0 net/vmw_vsock/virtio_transport_common.c:1387 vsock_loopback_work+0x3bb/0x5a0 net/vmw_vsock/vsock_loopback.c:120 process_one_work kernel/workqueue.c:2630 [inline] process_scheduled_works+0xff6/0x1e60 kernel/workqueue.c:2703 worker_thread+0xeca/0x14d0 kernel/workqueue.c:2784 kthread+0x3cc/0x520 kernel/kthread.c:388 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 CPU: 1 PID: 10664 Comm: kworker/1:5 Not tainted 6.6.0-rc3-00146-g9f3ebbef746f #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 Workqueue: vsock-loopback vsock_loopback_work ===================================================== The following simple reproducer can cause the issue described above: int main(void) { int sock; struct sockaddr_vm addr = { .svm_family = AF_VSOCK, .svm_cid = VMADDR_CID_ANY, .svm_port = 1234, }; sock = socket(AF_VSOCK, SOCK_STREAM, 0); connect(sock, (struct sockaddr *)&addr, sizeof(addr)); return 0; } This issue occurs because the `buf_alloc` and `fwd_cnt` fields of the `struct virtio_vsock_hdr` are not initialized when a new skb is allocated in `virtio_transport_init_hdr()`. This patch resolves the issue by initializing these fields during allocation. Fixes: 71dc9ec ("virtio/vsock: replace virtio_vsock_pkt with sk_buff") Reported-and-tested-by: syzbot+0c8ce1da0ac31abbadcd@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=0c8ce1da0ac31abbadcd Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://lore.kernel.org/r/20231104150531.257952-1-syoshida@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

====================================================== WARNING: possible circular locking dependency detected 6.5.0-kfd-yangp #2289 Not tainted ------------------------------------------------------ kworker/0:2/996 is trying to acquire lock: (srcu){.+.+}-{0:0}, at: __synchronize_srcu+0x5/0x1a0 but task is already holding lock: ((work_completion)(&svms->deferred_list_work)){+.+.}-{0:0}, at: process_one_work+0x211/0x560 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ((work_completion)(&svms->deferred_list_work)){+.+.}-{0:0}: __flush_work+0x88/0x4f0 svm_range_list_lock_and_flush_work+0x3d/0x110 [amdgpu] svm_range_set_attr+0xd6/0x14c0 [amdgpu] kfd_ioctl+0x1d1/0x630 [amdgpu] __x64_sys_ioctl+0x88/0xc0 -> #2 (&info->lock#2){+.+.}-{3:3}: __mutex_lock+0x99/0xc70 amdgpu_amdkfd_gpuvm_restore_process_bos+0x54/0x740 [amdgpu] restore_process_helper+0x22/0x80 [amdgpu] restore_process_worker+0x2d/0xa0 [amdgpu] process_one_work+0x29b/0x560 worker_thread+0x3d/0x3d0 -> #1 ((work_completion)(&(&process->restore_work)->work)){+.+.}-{0:0}: __flush_work+0x88/0x4f0 __cancel_work_timer+0x12c/0x1c0 kfd_process_notifier_release_internal+0x37/0x1f0 [amdgpu] __mmu_notifier_release+0xad/0x240 exit_mmap+0x6a/0x3a0 mmput+0x6a/0x120 do_exit+0x322/0xb90 do_group_exit+0x37/0xa0 __x64_sys_exit_group+0x18/0x20 do_syscall_64+0x38/0x80 -> #0 (srcu){.+.+}-{0:0}: __lock_acquire+0x1521/0x2510 lock_sync+0x5f/0x90 __synchronize_srcu+0x4f/0x1a0 __mmu_notifier_release+0x128/0x240 exit_mmap+0x6a/0x3a0 mmput+0x6a/0x120 svm_range_deferred_list_work+0x19f/0x350 [amdgpu] process_one_work+0x29b/0x560 worker_thread+0x3d/0x3d0 other info that might help us debug this: Chain exists of: srcu --> &info->lock#2 --> (work_completion)(&svms->deferred_list_work) Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((work_completion)(&svms->deferred_list_work)); lock(&info->lock#2); lock((work_completion)(&svms->deferred_list_work)); sync(srcu); Signed-off-by: Philip Yang <Philip.Yang@amd.com> Reviewed-by: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The variable rmnet_link_ops assign a *bigger* maxtype which leads to a global out-of-bounds read when parsing the netlink attributes. See bug trace below: ================================================================== BUG: KASAN: global-out-of-bounds in validate_nla lib/nlattr.c:386 [inline] BUG: KASAN: global-out-of-bounds in __nla_validate_parse+0x24af/0x2750 lib/nlattr.c:600 Read of size 1 at addr ffffffff92c438d0 by task syz-executor.6/84207 CPU: 0 PID: 84207 Comm: syz-executor.6 Tainted: G N 6.1.0 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x8b/0xb3 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x172/0x475 mm/kasan/report.c:395 kasan_report+0xbb/0x1c0 mm/kasan/report.c:495 validate_nla lib/nlattr.c:386 [inline] __nla_validate_parse+0x24af/0x2750 lib/nlattr.c:600 __nla_parse+0x3e/0x50 lib/nlattr.c:697 nla_parse_nested_deprecated include/net/netlink.h:1248 [inline] __rtnl_newlink+0x50a/0x1880 net/core/rtnetlink.c:3485 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3594 rtnetlink_rcv_msg+0x43c/0xd70 net/core/rtnetlink.c:6091 netlink_rcv_skb+0x14f/0x410 net/netlink/af_netlink.c:2540 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x54e/0x800 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x930/0xe50 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0x154/0x190 net/socket.c:734 ____sys_sendmsg+0x6df/0x840 net/socket.c:2482 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536 __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fdcf2072359 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdcf13e3168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fdcf219ff80 RCX: 00007fdcf2072359 RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000000000003 RBP: 00007fdcf20bd493 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffbb8d7bdf R14: 00007fdcf13e3300 R15: 0000000000022000 </TASK> The buggy address belongs to the variable: rmnet_policy+0x30/0xe0 The buggy address belongs to the physical page: page:0000000065bdeb3c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x155243 flags: 0x200000000001000(reserved|node=0|zone=2) raw: 0200000000001000 ffffea00055490c8 ffffea00055490c8 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffffffff92c43780: f9 f9 f9 f9 00 00 00 02 f9 f9 f9 f9 00 00 00 07 ffffffff92c43800: f9 f9 f9 f9 00 00 00 05 f9 f9 f9 f9 06 f9 f9 f9 >ffffffff92c43880: f9 f9 f9 f9 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 ^ ffffffff92c43900: 00 00 00 00 00 00 00 00 07 f9 f9 f9 f9 f9 f9 f9 ffffffff92c43980: 00 00 00 07 f9 f9 f9 f9 00 00 00 05 f9 f9 f9 f9 According to the comment of `nla_parse_nested_deprecated`, the maxtype should be len(destination array) - 1. Hence use `IFLA_RMNET_MAX` here. Fixes: 14452ca ("net: qualcomm: rmnet: Export mux_id and flags to netlink") Signed-off-by: Lin Ma <linma@zju.edu.cn> Reviewed-by: Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com> Reviewed-by: Simon Horman <horms@kernel.org> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/20240110061400.3356108-1-linma@zju.edu.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org>

…n,npcm750-pwm-fan Commit 89fec12 ("hwmon: (npcm750-pwm-fan) Add NPCM8xx support") introduced support for PWM fans on Nuvoton's npcm845 SoC. This chip supports three PWM modules with four PWM channels each. The older npcm750 only supported two PWM modules. The commit did not take into account that the older SoC only supported two PWM modules. This results in a crash if npcm750 is instantiated when the code attempts to instantiate the non-existing third PWM module. Unable to handle kernel paging request at virtual address e0aa2000 when write [e0aa2000] *pgd=04ab6811, *pte=00000000, *ppte=00000000 Internal error: Oops: 807 [#1] SMP ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Tainted: G N 6.7.0-next-20240112-dirty #3 Hardware name: NPCM7XX Chip family PC is at npcm7xx_pwm_fan_probe+0x204/0x890 LR is at arm_heavy_mb+0x1c/0x38 Fix the problem by detecting the number of supported PWM modules in the probe function and only instantiating the supported modules. Fixes: 89fec12 ("hwmon: (npcm750-pwm-fan) Add NPCM8xx support") Cc: Tomer Maimon <tmaimon77@gmail.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

The test_tag test triggers an unhandled page fault: # ./test_tag [ 130.640218] CPU 0 Unable to handle kernel paging request at virtual address ffff80001b898004, era == 9000000003137f7c, ra == 9000000003139e70 [ 130.640501] Oops[#3]: [ 130.640553] CPU: 0 PID: 1326 Comm: test_tag Tainted: G D O 6.7.0-rc4-loong-devel-gb62ab1a397cf #47 61985c1d94084daa2432f771daa45b56b10d8d2a [ 130.640764] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022 [ 130.640874] pc 9000000003137f7c ra 9000000003139e70 tp 9000000104cb4000 sp 9000000104cb7a40 [ 130.641001] a0 ffff80001b894000 a1 ffff80001b897ff8 a2 000000006ba210be a3 0000000000000000 [ 130.641128] a4 000000006ba210be a5 00000000000000f1 a6 00000000000000b3 a7 0000000000000000 [ 130.641256] t0 0000000000000000 t1 00000000000007f6 t2 0000000000000000 t3 9000000004091b70 [ 130.641387] t4 000000006ba210be t5 0000000000000004 t6 fffffffffffffff0 t7 90000000040913e0 [ 130.641512] t8 0000000000000005 u0 0000000000000dc0 s9 0000000000000009 s0 9000000104cb7ae0 [ 130.641641] s1 00000000000007f6 s2 0000000000000009 s3 0000000000000095 s4 0000000000000000 [ 130.641771] s5 ffff80001b894000 s6 ffff80001b897fb0 s7 9000000004090c50 s8 0000000000000000 [ 130.641900] ra: 9000000003139e70 build_body+0x1fcc/0x4988 [ 130.642007] ERA: 9000000003137f7c build_body+0xd8/0x4988 [ 130.642112] CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE) [ 130.642261] PRMD: 00000004 (PPLV0 +PIE -PWE) [ 130.642353] EUEN: 00000003 (+FPE +SXE -ASXE -BTE) [ 130.642458] ECFG: 00071c1c (LIE=2-4,10-12 VS=7) [ 130.642554] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0) [ 130.642658] BADV: ffff80001b898004 [ 130.642719] PRID: 0014c010 (Loongson-64bit, Loongson-3A5000) [ 130.642815] Modules linked in: [last unloaded: bpf_testmod(O)] [ 130.642924] Process test_tag (pid: 1326, threadinfo=00000000f7f4015f, task=000000006499f9fd) [ 130.643062] Stack : 0000000000000000 9000000003380724 0000000000000000 0000000104cb7be8 [ 130.643213] 0000000000000000 25af8d9b6e600558 9000000106250ea0 9000000104cb7ae0 [ 130.643378] 0000000000000000 0000000000000000 9000000104cb7be8 90000000049f6000 [ 130.643538] 0000000000000090 9000000106250ea0 ffff80001b894000 ffff80001b894000 [ 130.643685] 00007ffffb917790 900000000313ca94 0000000000000000 0000000000000000 [ 130.643831] ffff80001b894000 0000000000000ff7 0000000000000000 9000000100468000 [ 130.643983] 0000000000000000 0000000000000000 0000000000000040 25af8d9b6e600558 [ 130.644131] 0000000000000bb7 ffff80001b894048 0000000000000000 0000000000000000 [ 130.644276] 9000000104cb7be8 90000000049f6000 0000000000000090 9000000104cb7bdc [ 130.644423] ffff80001b894000 0000000000000000 00007ffffb917790 90000000032acfb0 [ 130.644572] ... [ 130.644629] Call Trace: [ 130.644641] [<9000000003137f7c>] build_body+0xd8/0x4988 [ 130.644785] [<900000000313ca94>] bpf_int_jit_compile+0x228/0x4ec [ 130.644891] [<90000000032acfb0>] bpf_prog_select_runtime+0x158/0x1b0 [ 130.645003] [<90000000032b3504>] bpf_prog_load+0x760/0xb44 [ 130.645089] [<90000000032b6744>] __sys_bpf+0xbb8/0x2588 [ 130.645175] [<90000000032b8388>] sys_bpf+0x20/0x2c [ 130.645259] [<9000000003f6ab38>] do_syscall+0x7c/0x94 [ 130.645369] [<9000000003121c5c>] handle_syscall+0xbc/0x158 [ 130.645507] [ 130.645539] Code: 380839f6 380831f9 28412bae <24000ca6> 004081ad 0014cb50 004083e8 02bff34c 58008e91 [ 130.645729] [ 130.646418] ---[ end trace 0000000000000000 ]--- On my machine, which has CONFIG_PAGE_SIZE_16KB=y, the test failed at loading a BPF prog with 2039 instructions: prog = (struct bpf_prog *)ffff80001b894000 insn = (struct bpf_insn *)(prog->insnsi)ffff80001b894048 insn + 2039 = (struct bpf_insn *)ffff80001b898000 <- end of the page In the build_insn() function, we are trying to access next instruction unconditionally, i.e. `(insn + 1)->imm`. The address lies in the next page and can be not owned by the current process, thus an page fault is inevitable and then segfault. So, let's access next instruction only under `dst = imm64` context. With this fix, we have: # ./test_tag test_tag: OK (40945 tests) Fixes: bbfddb9 ("LoongArch: BPF: Avoid declare variables in switch-case") Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Andrii Nakryiko says: ==================== Tighten up arg:ctx type enforcement Follow up fixes for kernel-side and libbpf-side logic around handling arg:ctx (__arg_ctx) tagged arguments of BPF global subprogs. Patch #1 adds libbpf feature detection of kernel-side __arg_ctx support to avoid unnecessary rewriting BTF types. With stricter kernel-side type enforcement this is now mandatory to avoid problems with using `struct bpf_user_pt_regs_t` instead of actual typedef. For __arg_ctx tagged arguments verifier is now supporting either `bpf_user_pt_regs_t` typedef or resolves it down to the actual struct (pt_regs/user_pt_regs/user_regs_struct), depending on architecture), but for old kernels without __arg_ctx support it's more backwards compatible for libbpf to use `struct bpf_user_pt_regs_t` rewrite which will work on wider range of kernels. So feature detection prevent libbpf accidentally breaking global subprogs on new kernels. We also adjust selftests to do similar feature detection (much simpler, but potentially breaking due to kernel source code refactoring, which is fine for selftests), and skip tests expecting libbpf's BTF type rewrites. Patch #2 is preparatory refactoring for patch #3 which adds type enforcement for arg:ctx tagged global subprog args. See the patch for specifics. Patch #4 adds many new cases to ensure type logic works as expected. Finally, patch #5 adds a relevant subset of kernel-side type checks to __arg_ctx cases that libbpf supports rewrite of. In libbpf's case, type violations are reported as warnings and BTF rewrite is not performed, which will eventually lead to BPF verifier complaining at program verification time. Good care was taken to avoid conflicts between bpf and bpf-next tree (which has few follow up refactorings in the same code area). Once trees converge some of the code will be moved around a bit (and some will be deleted), but with no change to functionality or general shape of the code. v2->v3: - support `bpf_user_pt_regs_t` typedef for KPROBE and PERF_EVENT (CI); v1->v2: - add user_pt_regs and user_regs_struct support for PERF_EVENT (CI); - drop FEAT_ARG_CTX_TAG enum leftover from patch #1; - fix warning about default: without break in the switch (CI). ==================== Link: https://lore.kernel.org/r/20240118033143.3384355-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Petr Machata says: ==================== mlxsw: Miscellaneous fixes This patchset is a bric-a-brac of fixes for bugs impacting mlxsw. - Patches #1 and #2 fix issues in ACL handling error paths. - Patch #3 fixes stack corruption in ACL code that a recent FW update has uncovered. - Patch #4 fixes an issue in handling of IPIP next hops. - Patch #5 fixes a typo in a the qos_pfc selftest - Patch #6 fixes the same selftest to work with 8-lane ports. ==================== Link: https://lore.kernel.org/r/cover.1705502064.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>

When I was testing mongodb over bcachefs with compression, there is a lockdep warning when snapshotting mongodb data volume. $ cat test.sh prog=bcachefs $prog subvolume create /mnt/data $prog subvolume create /mnt/data/snapshots while true;do $prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s) sleep 1s done $ cat /etc/mongodb.conf systemLog: destination: file logAppend: true path: /mnt/data/mongod.log storage: dbPath: /mnt/data/ lockdep reports: [ 3437.452330] ====================================================== [ 3437.452750] WARNING: possible circular locking dependency detected [ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G E [ 3437.453562] ------------------------------------------------------ [ 3437.453981] bcachefs/35533 is trying to acquire lock: [ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190 [ 3437.454875] but task is already holding lock: [ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.456009] which lock already depends on the new lock. [ 3437.456553] the existing dependency chain (in reverse order) is: [ 3437.457054] -> #3 (&type->s_umount_key#48){.+.+}-{3:3}: [ 3437.457507] down_read+0x3e/0x170 [ 3437.457772] bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.458206] __x64_sys_ioctl+0x93/0xd0 [ 3437.458498] do_syscall_64+0x42/0xf0 [ 3437.458779] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.459155] -> #2 (&c->snapshot_create_lock){++++}-{3:3}: [ 3437.459615] down_read+0x3e/0x170 [ 3437.459878] bch2_truncate+0x82/0x110 [bcachefs] [ 3437.460276] bchfs_truncate+0x254/0x3c0 [bcachefs] [ 3437.460686] notify_change+0x1f1/0x4a0 [ 3437.461283] do_truncate+0x7f/0xd0 [ 3437.461555] path_openat+0xa57/0xce0 [ 3437.461836] do_filp_open+0xb4/0x160 [ 3437.462116] do_sys_openat2+0x91/0xc0 [ 3437.462402] __x64_sys_openat+0x53/0xa0 [ 3437.462701] do_syscall_64+0x42/0xf0 [ 3437.462982] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.463359] -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}: [ 3437.463843] down_write+0x3b/0xc0 [ 3437.464223] bch2_write_iter+0x5b/0xcc0 [bcachefs] [ 3437.464493] vfs_write+0x21b/0x4c0 [ 3437.464653] ksys_write+0x69/0xf0 [ 3437.464839] do_syscall_64+0x42/0xf0 [ 3437.465009] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.465231] -> #0 (sb_writers#10){.+.+}-{0:0}: [ 3437.465471] __lock_acquire+0x1455/0x21b0 [ 3437.465656] lock_acquire+0xc6/0x2b0 [ 3437.465822] mnt_want_write+0x46/0x1a0 [ 3437.465996] filename_create+0x62/0x190 [ 3437.466175] user_path_create+0x2d/0x50 [ 3437.466352] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs] [ 3437.466617] __x64_sys_ioctl+0x93/0xd0 [ 3437.466791] do_syscall_64+0x42/0xf0 [ 3437.466957] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.467180] other info that might help us debug this: [ 3437.469670] 2 locks held by bcachefs/35533: other info that might help us debug this: [ 3437.467507] Chain exists of: sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48 [ 3437.467979] Possible unsafe locking scenario: [ 3437.468223] CPU0 CPU1 [ 3437.468405] ---- ---- [ 3437.468585] rlock(&type->s_umount_key#48); [ 3437.468758] lock(&c->snapshot_create_lock); [ 3437.469030] lock(&type->s_umount_key#48); [ 3437.469291] rlock(sb_writers#10); [ 3437.469434] *** DEADLOCK *** [ 3437.469670] 2 locks held by bcachefs/35533: [ 3437.469838] #0: ffffa0a02ce00a88 (&c->snapshot_create_lock){++++}-{3:3}, at: bch2_fs_file_ioctl+0x1e3/0xc90 [bcachefs] [ 3437.470294] #1: ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs] [ 3437.470744] stack backtrace: [ 3437.470922] CPU: 7 PID: 35533 Comm: bcachefs Kdump: loaded Tainted: G E 6.7.0-rc7-custom+ #85 [ 3437.471313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 3437.471694] Call Trace: [ 3437.471795] <TASK> [ 3437.471884] dump_stack_lvl+0x57/0x90 [ 3437.472035] check_noncircular+0x132/0x150 [ 3437.472202] __lock_acquire+0x1455/0x21b0 [ 3437.472369] lock_acquire+0xc6/0x2b0 [ 3437.472518] ? filename_create+0x62/0x190 [ 3437.472683] ? lock_is_held_type+0x97/0x110 [ 3437.472856] mnt_want_write+0x46/0x1a0 [ 3437.473025] ? filename_create+0x62/0x190 [ 3437.473204] filename_create+0x62/0x190 [ 3437.473380] user_path_create+0x2d/0x50 [ 3437.473555] bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs] [ 3437.473819] ? lock_acquire+0xc6/0x2b0 [ 3437.474002] ? __fget_files+0x2a/0x190 [ 3437.474195] ? __fget_files+0xbc/0x190 [ 3437.474380] ? lock_release+0xc5/0x270 [ 3437.474567] ? __x64_sys_ioctl+0x93/0xd0 [ 3437.474764] ? __pfx_bch2_fs_file_ioctl+0x10/0x10 [bcachefs] [ 3437.475090] __x64_sys_ioctl+0x93/0xd0 [ 3437.475277] do_syscall_64+0x42/0xf0 [ 3437.475454] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 3437.475691] RIP: 0033:0x7f2743c313af ====================================================== In __bch2_ioctl_subvolume_create(), we grab s_umount unconditionally and unlock it at the end of the function. There is a comment "why do we need this lock?" about the lock coming from commit 42d2373 ("bcachefs: Snapshot creation, deletion") The reason is that __bch2_ioctl_subvolume_create() calls sync_inodes_sb() which enforce locked s_umount to writeback all dirty nodes before doing snapshot works. Fix it by read locking s_umount for snapshotting only and unlocking s_umount after sync_inodes_sb(). Signed-off-by: Su Yue <glass.su@suse.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

pcmoore added the enhancement label Nov 18, 2016

pcmoore changed the title ~~always return a value from the netport/netnode/netif caches~~ RFE: always return a value from the netport/netnode/netif caches Nov 18, 2016

pcmoore added priority/low priority/medium and removed priority/low labels Nov 18, 2016

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RFE: always return a value from the netport/netnode/netif caches #3

RFE: always return a value from the netport/netnode/netif caches #3

stephensmalley commented Nov 17, 2016

RFE: always return a value from the netport/netnode/netif caches #3

RFE: always return a value from the netport/netnode/netif caches #3

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stephensmalley commented Nov 17, 2016