INFO: task syz-executor.4:11475 blocked for more than 140 seconds. Not tainted 4.19.80 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28216 11475 7645 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 schedule_timeout+0x8c8/0xfc0 kernel/time/timer.c:1782 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 vivid_stop_generating_vid_cap+0x1e0/0x6e2 drivers/media/platform/vivid/vivid-kthread-cap.c:922 vid_cap_stop_streaming+0x8a/0xe0 drivers/media/platform/vivid/vivid-vid-cap.c:256 __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: 0033:0x413741 Code: 00 00 00 48 c7 44 24 18 01 00 00 00 e8 68 00 00 00 48 8b 44 24 20 48 8b 4c 24 38 48 8b 54 24 30 0f b6 14 0a 80 fa a1 75 13 89 <44> 24 60 48 89 4c 24 68 48 8b 6c 24 40 48 83 c4 48 c3 48 8d 05 03 RSP: 002b:00007ffea54b5f30 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000413741 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: ffffffff816ffb39 R09: 00000000f1b0d8da R10: 00007ffea54b6010 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000004169a R14: 0000000000760db0 R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1037: #0: 00000000cea01b18 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4438 2 locks held by getty/7591: #0: 000000008a60c0cf (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000099fa8223 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7592: #0: 000000004fb807b6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000c243fe40 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7593: #0: 000000007d1574c4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000eaba09d8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7594: #0: 000000002c999d6c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000008ed3733 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7595: #0: 000000004ea401a9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000c515c73c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7596: #0: 00000000ca494c20 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000195f7a4b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7597: #0: 000000008f107fe1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 0000000023347dd7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1037 Comm: khungtaskd Not tainted 4.19.80 #0 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: 8234 Comm: kworker/u4:5 Not tainted 4.19.80 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0x31/0x49c0 kernel/locking/lockdep.c:3270 Code: 89 ff 41 56 41 55 45 89 cd 41 54 41 89 cc 53 89 d3 48 ba 00 00 00 00 00 fc ff df 48 83 e4 f0 48 81 ec a0 01 00 00 48 8b 45 10 <48> c7 84 24 a0 00 00 00 b3 8a b5 41 48 c7 84 24 a8 00 00 00 20 3e RSP: 0018:ffff88805322fa10 EFLAGS: 00000082 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff8879d7e0 RBP: ffff88805322fbd8 R08: 0000000000000000 R09: 0000000000000000 R10: ffffed1015d24732 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8879d7e0 FS: 0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c43284e000 CR3: 000000008b376000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903 rcu_lock_acquire include/linux/rcupdate.h:242 [inline] rcu_read_lock include/linux/rcupdate.h:627 [inline] batadv_nc_process_nc_paths.part.0+0xe4/0x3c0 net/batman-adv/network-coding.c:698 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:690 [inline] batadv_nc_worker+0x550/0x760 net/batman-adv/network-coding.c:739 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415