INFO: task kworker/u4:0:7 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:0 D24432 7 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/u4:3:3258 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:3 D27744 3258 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: 2 locks held by kworker/u4:0/7: #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:250 [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:856 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [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: ffffc90000cdfdc0 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 1 lock held by khungtaskd/1163: #0: ffffffff899befc0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 2 locks held by kworker/1:2/2709: 1 lock held by in:imklog/6817: #0: ffff8880a8095bb0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 1 lock held by syz-executor.3/9889: #0: ffffffff899c3020 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline] #0: ffffffff899c3020 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x501/0x620 kernel/rcu/tree_exp.h:856 2 locks held by kworker/u4:3/3258: #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:250 [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:856 [inline] #0: ffff8880aa034138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [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: ffffc90019087dc0 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x878/0x16a0 kernel/workqueue.c:2243 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1163 Comm: khungtaskd Not tainted 5.7.0-rc1-next-20200415-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:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:249 [inline] watchdog+0xde3/0x14e0 kernel/hung_task.c:333 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: 2709 Comm: kworker/1:2 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_read_work RIP: 0010:match_held_lock+0x66/0x500 kernel/locking/lockdep.c:4417 Code: 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 84 03 00 00 <66> f7 43 22 f0 ff 0f 84 ac 01 00 00 48 8d 7e 08 48 b8 00 00 00 00 RSP: 0018:ffffc90008a578e8 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff88809fe4ee50 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff899bef60 RDI: ffff88809fe4ee72 RBP: ffff88809fe4e580 R08: ffffffff8602647e R09: ffffed1013fc9cb1 R10: ffffc90008a57b28 R11: ffffed1013fc9cb0 R12: ffffed1013fc9dc9 R13: ffff88809fe4ee50 R14: ffff88809fe4ee48 R15: ffffffff899bef60 FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8a76ce2000 CR3: 00000000a8c8f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:4708 [inline] lock_is_held_type+0x1a6/0x350 kernel/locking/lockdep.c:4971 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