INFO: task syz-executor4:29880 blocked for more than 140 seconds. Not tainted 4.20.0-rc6+ #153 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor4 D22968 29880 28073 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_queue_release+0x26/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2255 vb2_queue_release+0x15/0x20 drivers/media/common/videobuf2/videobuf2-v4l2.c:842 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: 0033:0x457659 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:00007f2c70d0bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000457659 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c70d0c6d4 R13: 00000000004f16d2 R14: 00000000004cd578 R15: 00000000ffffffff Showing all locks held in the system: 2 locks held by kworker/0:0/5: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000007c521528 ((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: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000e558ddda ((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: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000008d2a3411 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 1 lock held by khungtaskd/1019: #0: 00000000ec0af8d1 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/6059: #0: 000000009f4aa342 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/6181: #0: 00000000590f6c07 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000005afdc786 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6182: #0: 00000000b51fa536 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000008277746b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6183: #0: 00000000bdf67b62 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ea3b9bb4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6184: #0: 00000000c1004cb2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a84ab220 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6185: #0: 000000007c1cca48 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000e1b87e00 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6186: #0: 000000008b0469a2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000066d10d2e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/6187: #0: 000000009f0f9719 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000de9e1ad1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by kworker/0:2/6316: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 000000006de9bdbe ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:3/6412: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000c97c1420 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:4/19057: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000ed7b8d03 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:6/23149: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000f2e74942 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:7/23155: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000a18d6d3f ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by kworker/0:8/23171: #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000000373671c ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124 #1: 00000000ad3b13c7 ((work_completion)(&smc->tcp_listen_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128 2 locks held by syz-executor4/29880: #0: 00000000c9b7e4ec (&mdev->req_queue_mutex){+.+.}, at: v4l2_release+0x1d7/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:455 #1: 0000000003c628e2 (&dev->dev_mutex){+.+.}, at: vim2m_release+0xbc/0x150 drivers/media/platform/vim2m.c:976 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1019 Comm: khungtaskd Not tainted 4.20.0-rc6+ #153 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+ #153 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_dynticks_curr_cpu_in_eqs+0x12/0x170 kernel/rcu/tree.c:289 Code: ff 65 48 8b 3c 25 40 ee 01 00 e8 e9 bc ff ff 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 41 56 49 be 00 00 00 00 00 fc ff df 41 55 <4c> 8d 6d e0 41 54 49 c7 c4 40 da 02 00 53 48 8d 5d 80 48 c1 eb 03 RSP: 0018:ffff8881daf07aa0 EFLAGS: 00000286 RAX: 0000000000000001 RBX: ffffffff8a1673b4 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffed103b5e0f8c RDI: ffff8881d9b20bbc RBP: ffff8881daf07ab0 R08: ffff8881d9b20340 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000040 R13: 0000000000000008 R14: dffffc0000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001bc311000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_is_watching+0x10/0x30 kernel/rcu/tree.c:906 rcu_read_lock_sched_held+0x91/0x180 kernel/rcu/update.c:112 trace_softirq_entry include/trace/events/irq.h:128 [inline] __do_softirq+0x979/0xb7e kernel/softirq.c:291 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x17f/0x1c0 kernel/softirq.c:413 scheduler_ipi+0x55a/0xad0 kernel/sched/core.c:1785 smp_reschedule_interrupt+0x109/0x650 arch/x86/kernel/smp.c:278 reschedule_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:831 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57 Code: e9 2c ff ff ff 48 89 c7 48 89 45 d8 e8 f3 c0 e7 f9 48 8b 45 d8 e9 ca fe ff ff 48 89 df e8 e2 c0 e7 f9 eb 82 55 48 89 e5 fb f4 <5d> c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 f4 5d c3 90 90 90 90 90 RSP: 0018:ffff8881d9b2fcb8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1103b365f9b RCX: 0000000000000000 RDX: 1ffffffff12a4021 RSI: 0000000000000001 RDI: ffffffff89520108 RBP: ffff8881d9b2fcb8 R08: ffff8881d9b20340 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d9b2fd78 R13: ffffffff8a1641a0 R14: 0000000000000000 R15: 0000000000000001 arch_safe_halt arch/x86/include/asm/paravirt.h:151 [inline] default_idle+0xbf/0x490 arch/x86/kernel/process.c:561 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:552 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x49b/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