INFO: task syz-executor5:17068 blocked for more than 140 seconds. Not tainted 4.20.0-rc6+ #371 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D22864 17068 6070 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136 flush_workqueue+0x742/0x1e10 kernel/workqueue.c:2707 flush_scheduled_work include/linux/workqueue.h:599 [inline] vim2m_stop_streaming+0x7c/0x2c0 drivers/media/platform/vim2m.c:811 __vb2_queue_cancel+0x171/0xd20 drivers/media/common/videobuf2/videobuf2-core.c:1823 vb2_core_queue_release+0x26/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2229 vb2_queue_release+0x15/0x20 drivers/media/common/videobuf2/videobuf2-v4l2.c:837 v4l2_m2m_ctx_release+0x1e/0x35 drivers/media/v4l2-core/v4l2-mem2mem.c:930 vim2m_release+0xe6/0x150 drivers/media/platform/vim2m.c:977 v4l2_release+0x224/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:456 __fput+0x385/0xa30 fs/file_table.c:278 ____fput+0x15/0x20 fs/file_table.c:309 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411111 Code: cc cc cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 0f 86 96 00 00 00 48 83 ec 28 48 89 6c 24 20 48 8d 6c 24 20 <48> 8b 4c 24 38 48 85 c9 7c 60 48 8b 54 24 30 48 8b 1a 48 83 fb 21 RSP: 002b:0000000000a3fd90 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411111 RDX: 0000000000000000 RSI: 00000000007306f8 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00000000007306f0 R09: 0000000000000000 R10: 0000000000a3fcb0 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000177 R15: 0000000000000005 INFO: task syz-executor5:17070 blocked for more than 140 seconds. Not tainted 4.20.0-rc6+ #371 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D24600 17070 6070 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3574 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xaff/0x16f0 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 v4l2_m2m_fop_poll+0x98/0x120 drivers/media/v4l2-core/v4l2-mem2mem.c:1105 v4l2_poll+0x153/0x200 drivers/media/v4l2-core/v4l2-dev.c:350 vfs_poll include/linux/poll.h:86 [inline] do_pollfd fs/select.c:825 [inline] do_poll fs/select.c:873 [inline] do_sys_poll+0x751/0x1180 fs/select.c:967 __do_sys_ppoll fs/select.c:1075 [inline] __se_sys_ppoll fs/select.c:1047 [inline] __x64_sys_ppoll+0x2fe/0x610 fs/select.c:1047 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457659 Code: fc ff 48 8b 44 24 08 48 8b 08 48 89 0c 24 e8 ee 27 fc ff e8 39 78 fc ff 48 8b 44 24 08 e9 95 fe ff ff e8 5a 28 00 00 e9 45 fe ff cc cc cc cc cc 48 8b 4c 24 10 48 8b 11 64 48 8b 1c 25 f8 ff RSP: 002b:00007f56a5d92c78 EFLAGS: 00000246 ORIG_RAX: 000000000000010f RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457659 RDX: 0000000020000140 RSI: 0000000000000001 RDI: 0000000020000100 RBP: 000000000072bf00 R08: 0000000000000008 R09: 0000000000000000 R10: 0000000020000180 R11: 0000000000000246 R12: 00007f56a5d936d4 R13: 00000000004c3589 R14: 00000000004d5eb8 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/0:0/5: #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000009cd9f972 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:1/12: #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000d61c4d25 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by khungtaskd/1021: #0: 00000000755616cd (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 2 locks held by kworker/0:2/2602: #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000bc994939 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by rsyslogd/5809: 2 locks held by getty/5899: #0: 00000000e23ba74a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000006798b3c3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5900: #0: 000000005b10696d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000000da661b3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5901: #0: 000000008e581742 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000002edefa71 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5902: #0: 000000001710a792 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ccb7e36b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5903: #0: 000000007c999ccc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000075bbce85 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5904: #0: 00000000560cd9f7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000044bf7bd4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5905: #0: 00000000c01fbfc0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000beb4ff2a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by kworker/1:3/6247: #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000888497ec ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/1:4/6251: #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000ffe9c3d9 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000aef6ad18 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by syz-executor5/17068: #0: 000000006e080e80 (&mdev->req_queue_mutex){+.+.}, at: v4l2_release+0x1d7/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:455 #1: 000000009c6019a0 (&dev->dev_mutex){+.+.}, at: vim2m_release+0xbc/0x150 drivers/media/platform/vim2m.c:976 1 lock held by syz-executor5/17070: #0: 000000009c6019a0 (&dev->dev_mutex){+.+.}, at: v4l2_m2m_fop_poll+0x98/0x120 drivers/media/v4l2-core/v4l2-mem2mem.c:1105 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1021 Comm: khungtaskd Not tainted 4.20.0-rc6+ #371 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb51/0x1060 kernel/hung_task.c:289 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.20.0-rc6+ #371 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:write_comp_data+0x1/0x70 kernel/kcov.c:116 Code: 55 66 43 00 e9 a6 fc ff ff 4c 89 f7 e8 a8 65 43 00 e9 6f fc ff ff e8 ae 64 c9 ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <48> 89 e5 65 4c 8b 04 25 40 ee 01 00 65 8b 05 bc 69 82 7e a9 00 01 RSP: 0018:ffff8881d9b27af0 EFLAGS: 00000046 RAX: 000000cd42e4dffb RBX: dffffc0000000000 RCX: ffffffff816e6263 RDX: 000000000001f956 RSI: 000000000001f956 RDI: 0000000000000004 RBP: ffff8881d9b27b00 R08: ffff8881d9b14340 R09: 0000000000000008 R10: 0000000000000001 R11: ffff8881d9b14340 R12: 000000000001f956 R13: 000000cd42e4dffb R14: ffff8881d9b27b80 R15: 000000000001f956 FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbcfc343000 CR3: 00000001d8068000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: timekeeping_max_deferment+0x1f3/0x300 kernel/time/timekeeping.c:1464 tick_nohz_next_event+0x394/0x8a0 kernel/time/tick-sched.c:715 __tick_nohz_idle_stop_tick kernel/time/tick-sched.c:930 [inline] tick_nohz_idle_stop_tick+0x6bf/0xe10 kernel/time/tick-sched.c:960 cpuidle_idle_call kernel/sched/idle.c:150 [inline] do_idle+0x491/0x5c0 kernel/sched/idle.c:262 cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353 start_secondary+0x487/0x5f0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243