INFO: task syz-executor5:28065 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 D23400 28065 995 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_release+0x1d7/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:455 __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: 0033:0x411131 Code: 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 73 3b 48 8d 05 70 46 78 00 48 <8b> 04 d8 48 39 c1 77 42 48 0f af d9 48 89 1c 24 48 89 54 24 08 c6 RSP: 002b:0000000000a3fd90 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411131 RDX: 0000000000000000 RSI: 0000000000730f08 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000a3fcc0 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 000000000000043a R15: 0000000000000005 INFO: task syz-executor5:28066 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 D22192 28066 995 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: 0033:0x457679 Code: ff ff e8 5a 28 00 00 e9 45 fe ff ff cc cc cc cc cc 48 8b 4c 24 10 48 8b 11 64 48 8b 1c 25 f8 ff ff ff 8b b2 d8 00 00 00 8d 7e 89 ba d8 00 00 00 83 fe 01 75 13 0f b6 93 c0 00 00 00 84 d2 74 RSP: 002b:00007f441e666c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000457679 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f441e6676d4 R13: 00000000004f16f2 R14: 00000000004cd598 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/1:0/17: #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000c09e285e ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by khungtaskd/1019: #0: 0000000076b0fecd (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5915: #0: 00000000b3cd29e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6005: #0: 00000000833758fd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001ba28257 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6006: #0: 0000000005e7b75b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009ccaad1c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6007: #0: 00000000ca30a28f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008713fa94 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6008: #0: 00000000b30206a7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001f36c97c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6009: #0: 000000008a0daaa0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000098a7b4ec (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6010: #0: 0000000009c106f7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ec6ffd9d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6011: #0: 0000000000d898f9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000024761559 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by kworker/1:9/15104: #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000132a7c6 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000e2192dac ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by syz-executor5/28065: #0: 0000000004314b62 (&mdev->req_queue_mutex){+.+.}, at: v4l2_release+0x1d7/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:455 2 locks held by syz-executor5/28066: #0: 0000000004314b62 (&mdev->req_queue_mutex){+.+.}, at: v4l2_release+0x1d7/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:455 #1: 00000000fe12f7c5 (&dev->dev_mutex){+.+.}, at: vim2m_release+0xbc/0x150 drivers/media/platform/vim2m.c:976 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1019 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 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57