INFO: task syz-executor2:18359 blocked for more than 140 seconds. Not tainted 4.20.0-rc6+ #151 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D22936 18359 16777 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+0x14f/0xd50 drivers/media/common/videobuf2/videobuf2-core.c:1843 vb2_core_streamoff+0x60/0x140 drivers/media/common/videobuf2/videobuf2-core.c:2006 vb2_streamoff+0x4a/0x90 drivers/media/common/videobuf2/videobuf2-v4l2.c:789 v4l2_m2m_streamoff+0xd0/0x720 drivers/media/v4l2-core/v4l2-mem2mem.c:563 v4l2_m2m_ioctl_streamoff+0x6b/0x80 drivers/media/v4l2-core/v4l2-mem2mem.c:1081 v4l_streamoff+0x76/0x90 drivers/media/v4l2-core/v4l2-ioctl.c:1698 __video_do_ioctl+0x8b1/0x1050 drivers/media/v4l2-core/v4l2-ioctl.c:2853 video_usercopy+0x5c1/0x1760 drivers/media/v4l2-core/v4l2-ioctl.c:3035 video_ioctl2+0x2c/0x33 drivers/media/v4l2-core/v4l2-ioctl.c:3079 v4l2_ioctl+0x154/0x1b0 drivers/media/v4l2-core/v4l2-dev.c:364 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 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:00007fdbf4224c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457659 RDX: 0000000020000080 RSI: 0000000040045613 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdbf42256d4 R13: 00000000004c1fb0 R14: 00000000004d3bd8 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/1:0/17: #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000438e0df6 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/1:1/22: #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000009681f4af ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by khungtaskd/1020: #0: 00000000f383d232 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5968: #0: 00000000c6101361 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6058: #0: 000000003000b651 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b8d31e0b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6059: #0: 00000000be960581 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000049532b45 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6060: #0: 0000000042cae468 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e9dd1d2b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6061: #0: 00000000887c7abb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a12eae39 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6062: #0: 0000000033e6f8f8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000b77d4d92 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6063: #0: 00000000f3f8e00f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000759be884 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6064: #0: 00000000607b2ec9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009f9140e4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by kworker/1:2/6146: #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000e1cd1f11 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:3/6386: #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000005192c238 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/1:5/7514: #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000bc3d22b3 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000002922eb22 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by syz-executor2/18359: #0: 0000000022a0f1aa (&mdev->req_queue_mutex){+.+.}, at: __video_do_ioctl+0xb6c/0x1050 drivers/media/v4l2-core/v4l2-ioctl.c:2815 #1: 000000005b315877 (&dev->dev_mutex){+.+.}, at: __video_do_ioctl+0x461/0x1050 drivers/media/v4l2-core/v4l2-ioctl.c:2821 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1020 Comm: khungtaskd Not tainted 4.20.0-rc6+ #151 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