INFO: task syz-executor.5:12872 blocked for more than 140 seconds. Not tainted 4.19.69 #43 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28216 12872 23425 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3474 schedule+0x92/0x1c0 kernel/sched/core.c:3518 schedule_timeout+0x8c8/0xfc0 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+0x29c/0x440 kernel/sched/completion.c:136 kthread_stop+0x116/0x6c0 kernel/kthread.c:550 sdr_cap_stop_streaming+0x213/0x330 drivers/media/platform/vivid/vivid-sdr-cap.c:301 __vb2_queue_cancel+0xb1/0x790 drivers/media/common/videobuf2/videobuf2-core.c:1682 vb2_core_streamoff+0x60/0x150 drivers/media/common/videobuf2/videobuf2-core.c:1816 __vb2_cleanup_fileio+0x78/0x170 drivers/media/common/videobuf2/videobuf2-core.c:2343 vb2_core_queue_release+0x20/0x80 drivers/media/common/videobuf2/videobuf2-core.c:2070 vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:671 [inline] _vb2_fop_release+0x1cf/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:842 vb2_fop_release+0x75/0xc0 drivers/media/common/videobuf2/videobuf2-v4l2.c:856 vivid_fop_release+0x18e/0x430 drivers/media/platform/vivid/vivid-core.c:474 v4l2_release+0xf9/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448 __fput+0x2dd/0x8b0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x53d/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x413561 Code: 94 d6 65 00 ba 02 00 00 00 bf 3a 38 44 00 ff 15 2d a1 24 00 85 c0 0f 85 e7 fd ff ff 31 c9 31 f6 41 b9 b0 20 41 00 41 b8 98 d6 <65> 00 ba 03 00 00 00 bf 44 38 44 00 ff 15 05 a1 24 00 85 c0 0f 85 RSP: 002b:00007fff35d314f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000413561 RDX: 0000001b2bc20000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: ffffffff81708b26 R09: 0000000013f8fe33 R10: 00007fff35d315d0 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000034e9c2 R14: 0000000000760380 R15: ffffffffffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1038: #0: 00000000a2262fbe (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4435 1 lock held by udevd/3602: 3 locks held by rs:main Q:Reg/7742: #0: 000000009dc13dd4 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 #1: 00000000749f0bb3 (sb_writers#4){.+.+}, at: file_start_write include/linux/fs.h:2775 [inline] #1: 00000000749f0bb3 (sb_writers#4){.+.+}, at: vfs_write+0x429/0x560 fs/read_write.c:548 #2: 000000006fe3515a (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1821 [inline] #2: 000000006fe3515a (&rq->lock){-.-.}, at: __schedule+0x1f8/0x1dc0 kernel/sched/core.c:3412 1 lock held by rsyslogd/7744: #0: 00000000c9ea9b64 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 2 locks held by getty/7866: #0: 00000000c668a8dd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000004b097b22 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7867: #0: 0000000064911d56 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000bd7de958 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7868: #0: 00000000a95d330c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000005d372bfc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7869: #0: 00000000601bad00 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000001d89e7a7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7870: #0: 00000000c4107c8d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000848ba834 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7871: #0: 000000002bab44ff (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000005d4f1322 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7872: #0: 00000000328ee5c5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000092d06e48 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1038 Comm: khungtaskd Not tainted 4.19.69 #43 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3602 Comm: udevd Not tainted 4.19.69 #43 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__raw_spin_lock_irq include/linux/spinlock_api_smp.h:129 [inline] RIP: 0010:_raw_spin_lock_irq+0x60/0x80 kernel/locking/spinlock.c:160 Code: 66 b9 7c fa bf 01 00 00 00 e8 8c 70 55 fa 45 31 c9 41 b8 01 00 00 00 31 c9 ff 75 08 49 8d 7c 24 18 31 d2 31 f6 e8 70 be 5e fa <4c> 89 e7 e8 68 83 5f fa 4c 8b 65 f8 58 c9 c3 0f 0b 48 c7 c7 10 46 RSP: 0018:ffff88809796fbd8 EFLAGS: 00000082 RAX: 1ffffffff10e48c1 RBX: ffffffff81bd98d0 RCX: 00000000efcd2ec0 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000082 RBP: ffff88809796fbe8 R08: 0000000000001a93 R09: 0000000000000001 R10: ffff888097962a68 R11: ffffffff89e61918 R12: ffff888097b7a380 R13: ffff88809796fdc0 R14: ffff888097b7a410 R15: ffff888097b7a380 FS: 00007f4243c8c7a0(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000000992b9000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_lock_irq include/linux/spinlock.h:354 [inline] ep_scan_ready_list+0x313/0xb20 fs/eventpoll.c:710 ep_send_events fs/eventpoll.c:1713 [inline] ep_poll+0x3b4/0xd10 fs/eventpoll.c:1840 do_epoll_wait+0x1b3/0x200 fs/eventpoll.c:2198 __do_sys_epoll_wait fs/eventpoll.c:2208 [inline] __se_sys_epoll_wait fs/eventpoll.c:2205 [inline] __x64_sys_epoll_wait+0x97/0xf0 fs/eventpoll.c:2205 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f42433a0943 Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24 RSP: 002b:00007ffe9b103ac8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f42433a0943 RDX: 0000000000000008 RSI: 00007ffe9b103bc0 RDI: 000000000000000a RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000c3bf50 R15: 0000000000c26030