INFO: task kworker/u4:5:8384 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:5 D25848 8384 2 0x80004000 Workqueue: events_unbound fsnotify_mark_destroy_workfn Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4163 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x16a/0x270 kernel/sched/completion.c:138 __synchronize_srcu+0x1a7/0x260 kernel/rcu/srcutree.c:922 fsnotify_mark_destroy_workfn+0xfd/0x330 fs/notify/mark.c:832 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INFO: task kworker/u4:6:8628 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:6 D24720 8628 2 0x80004000 Workqueue: events_unbound fsnotify_connector_destroy_workfn Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4163 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x16a/0x270 kernel/sched/completion.c:138 __synchronize_srcu+0x1a7/0x260 kernel/rcu/srcutree.c:922 fsnotify_connector_destroy_workfn+0x49/0xa0 fs/notify/mark.c:164 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 1 lock held by khungtaskd/1139: #0: ffffffff899bed00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 3 locks held by kworker/1:3/2716: 1 lock held by in:imklog/6705: #0: ffff8880a8ac7db0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by kworker/u4:5/8384: #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239 #1: ffffc90016cd7dc0 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 2 locks held by kworker/u4:6/8628: #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239 #1: ffffc90001597dc0 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1139 Comm: khungtaskd Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2716 Comm: kworker/1:3 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_read_work RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:417 [inline] RIP: 0010:lock_is_held_type+0x1f8/0x350 kernel/locking/lockdep.c:4972 Code: 04 02 84 c0 74 08 3c 03 0f 8e 20 01 00 00 41 0f b6 45 22 45 31 e4 83 e0 03 3b 44 24 0c 41 0f 94 c4 65 48 8b 1c 25 00 1f 02 00 <48> 8d bb c4 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc90007d67920 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880a031a440 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff899beca0 RDI: ffff8880a031ad52 RBP: ffff8880a031a440 R08: ffffffff85fc45be R09: ffffed1014063489 R10: ffffc90007d67b28 R11: ffffed1014063488 R12: 0000000000000000 R13: ffff8880a031ad30 R14: ffff8880a031ad00 R15: ffffffff899beca0 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6af651d000 CR3: 000000009fa3b000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:406 [inline] ___might_sleep+0x239/0x2b0 kernel/sched/core.c:6771 __mutex_lock_common kernel/locking/mutex.c:935 [inline] __mutex_lock+0xc5/0x13c0 kernel/locking/mutex.c:1103 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1490 [inline] snd_pcm_oss_read+0x32e/0x6f0 sound/core/oss/pcm_oss.c:2742 __vfs_read+0x76/0x100 fs/read_write.c:426 vfs_read+0x1f0/0x420 fs/read_write.c:462 kernel_read+0xaf/0x120 fs/read_write.c:441 p9_fd_read net/9p/trans_fd.c:263 [inline] p9_read_work+0x2aa/0xfa0 net/9p/trans_fd.c:298 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352