INFO: task syz-executor.5:7235 blocked for more than 140 seconds. Not tainted 4.14.152 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28528 7235 6890 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_timeout+0x93b/0xe10 kernel/time/timer.c:1723 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common kernel/sched/completion.c:123 [inline] wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144 kthread_stop+0xda/0x650 kernel/kthread.c:530 vivid_stop_generating_vid_cap+0x1b9/0x664 drivers/media/platform/vivid/vivid-kthread-cap.c:934 vid_cap_stop_streaming+0x7c/0xd0 drivers/media/platform/vivid/vivid-vid-cap.c:273 __vb2_queue_cancel+0xa3/0x890 drivers/media/v4l2-core/videobuf2-core.c:1655 vb2_core_streamoff+0x52/0x110 drivers/media/v4l2-core/videobuf2-core.c:1788 __vb2_cleanup_fileio+0x78/0x150 drivers/media/v4l2-core/videobuf2-core.c:2313 vb2_core_queue_release+0x1d/0x80 drivers/media/v4l2-core/videobuf2-core.c:2040 vb2_queue_release drivers/media/v4l2-core/videobuf2-v4l2.c:669 [inline] _vb2_fop_release+0x1cf/0x2a0 drivers/media/v4l2-core/videobuf2-v4l2.c:840 vb2_fop_release+0x75/0xc0 drivers/media/v4l2-core/videobuf2-v4l2.c:854 vivid_fop_release+0x180/0x3f0 drivers/media/platform/vivid/vivid-core.c:486 v4l2_release+0xf9/0x190 drivers/media/v4l2-core/v4l2-dev.c:446 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x413db1 RSP: 002b:00007ffc9d4b8920 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000413db1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 0000000000000001 R08: ffffffff8100799b R09: 000000006e783fbf R10: 00007ffc9d4b8a00 R11: 0000000000000293 R12: 000000000075bf20 R13: 00000000000152b3 R14: 0000000000760a48 R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1016: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 2 locks held by getty/6840: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6841: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6842: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6843: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6844: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6845: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/6846: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1016 Comm: khungtaskd Not tainted 4.14.152 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x197 lib/dump_stack.c:53 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e7/0xb90 kernel/hung_task.c:274 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.152 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a9d1c340 task.stack: ffff8880a9d28000 RIP: 0010:check_preemption_disabled+0xd/0x250 lib/smp_processor_id.c:13 RSP: 0018:ffff8880aef07c30 EFLAGS: 00000006 RAX: ffff8880a9d1c340 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000100 RSI: ffffffff869d32a0 RDI: ffffffff869d32e0 RBP: ffff8880aef07c48 R08: 0000000000004123 R09: ffffffff88ca1e58 R10: ffff8880a9d1cbc0 R11: ffff8880a9d1c340 R12: ffff8880a9d1cbc0 R13: ffffed10153a3977 R14: ffffffff869d32e0 R15: ffff8880a9d1c340 FS: 0000000000000000(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c42b1af010 CR3: 000000007cb45000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:57 prandom_u32+0x1f/0xa0 lib/random32.c:81 __lock_pin_lock kernel/locking/lockdep.c:3843 [inline] lock_pin_lock+0x1fe/0x390 kernel/locking/lockdep.c:4052 rq_pin_lock kernel/sched/sched.h:932 [inline] rq_lock_irqsave kernel/sched/sched.h:1730 [inline] update_blocked_averages+0x69/0x12c0 kernel/sched/fair.c:7031 rebalance_domains+0xc6/0xb40 kernel/sched/fair.c:8791 run_rebalance_domains+0x309/0x560 kernel/sched/fair.c:9052 __do_softirq+0x244/0x9a0 kernel/softirq.c:288 invoke_softirq kernel/softirq.c:368 [inline] irq_exit+0x160/0x1b0 kernel/softirq.c:409 scheduler_ipi+0x18b/0x4e0 kernel/sched/core.c:1811 smp_reschedule_interrupt+0x83/0x4f0 arch/x86/kernel/smp.c:286 reschedule_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:816 RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61 RSP: 0018:ffff8880a9d2fe70 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: 1ffffffff0ee2ab4 RBX: ffff8880a9d1c340 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880a9d1cbbc RBP: ffff8880a9d2fe98 R08: 1ffffffff104ac01 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff87715590 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880a9d1c340 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:557 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x262/0x3d0 kernel/sched/idle.c:246 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:351 start_secondary+0x346/0x4b0 arch/x86/kernel/smpboot.c:272 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 Code: ff ff e8 d7 3d ae fe e9 2f f2 ff ff e8 ad 3e ae fe e9 5b f1 ff ff 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 49 89 fe 41 55 <49> 89 f5 41 54 53 48 83 ec 08 e8 f4 8a 84 fe 65 44 8b 25 1c 18