INFO: task syz-executor.2:11040 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28528 11040 7071 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_timeout+0x93d/0xe10 kernel/time/timer.c:1721 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+0xa6/0x8a0 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+0xfb/0x190 drivers/media/v4l2-core/v4l2-dev.c:446 __fput+0x277/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x119/0x190 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:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:267 [inline] do_syscall_64+0x4a9/0x630 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4120b1 RSP: 002b:00007fff6de13ab0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00000000004120b1 RDX: 0000001b2d420000 RSI: 0000000000740160 RDI: 0000000000000003 RBP: 000000000073c900 R08: 0000000015c23545 R09: 0000000015c23549 R10: 00007fff6de13b80 R11: 0000000000000293 R12: ffffffffffffffff R13: 000000000001fe61 R14: 00000000000003e8 R15: 000000000073bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1009: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 2 locks held by getty/7024: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7025: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7026: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7027: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7028: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7029: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7030: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1009 Comm: khungtaskd Not tainted 4.14.111 #1 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+0x138/0x19c 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:194 [inline] watchdog+0x5d8/0xb80 kernel/hung_task.c:250 kthread+0x31c/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2819 Comm: kworker/u4:5 Not tainted 4.14.111 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker task: ffff88809e39c000 task.stack: ffff88809dc68000 RIP: 0010:lock_acquire+0x198/0x430 kernel/locking/lockdep.c:3996 RSP: 0018:ffff88809dc6fc90 EFLAGS: 00000807 RAX: dffffc0000000000 RBX: ffff88809e39c000 RCX: 000000002e890d4b RDX: 0000000000000000 RSI: ffff88809e39c8d0 RDI: ffff88809e39c87c RBP: ffff88809dc6fcd8 R08: 0000000000000000 R09: ffff88809e39c8f0 R10: ffff88809e39c8d0 R11: ffff88809e39c000 R12: ffffffff8778ed60 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000b8c7e0 CR3: 00000000a8b83000 CR4: 00000000001406f0 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:244 [inline] rcu_read_lock include/linux/rcupdate.h:631 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x107/0x6d0 net/batman-adv/network-coding.c:726 process_one_work+0x868/0x1610 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x31c/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Code: ff ff 48 b8 00 00 00 00 00 fc ff df 65 48 8b 1c 25 40 ee 01 00 48 8d bb 7c 08 00 00 48 83 c4 20 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 17 02 00 00