INFO: task kworker/u4:9:10967 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u4:9 D25536 10967 2 0x80000000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 flush_workqueue+0x40b/0x13e0 kernel/workqueue.c:2713 flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:554 XFS (loop5): DAX enabled. Warning: EXPERIMENTAL, use at your own risk process_one_work+0x864/0x1570 kernel/workqueue.c:2153 XFS (loop5): DAX unsupported by block device. Turning off DAX. worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 XFS (loop5): Mounting V4 Filesystem kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Showing all locks held in the system: 1 lock held by khungtaskd/1570: #0: 000000003f335890 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 2 locks held by kworker/1:2/4384: #0: 00000000c38114a3 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 XFS (loop5): Ending clean mount #1: 00000000256d8361 ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 XFS (loop5): Quotacheck needed: Please wait. 1 lock held by in:imklog/7837: XFS (loop5): Quotacheck: Done. #0: 00000000eba75a15 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 3 locks held by kworker/u4:9/10967: #0: 000000002ea13333 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000ff820a21 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000f60cd003 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521 2 locks held by kworker/0:6/12318: #0: 00000000c38114a3 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000006dd95c27 ((work_completion)(&m->rq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 1 lock held by systemd-udevd/4563: #0: 0000000043059dd0 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9702 [inline] #0: 0000000043059dd0 (&rq->lock){-.-.}, at: pick_next_task_fair+0x556/0x1570 kernel/sched/fair.c:6841 ============================================= XFS (loop5): Unmounting Filesystem NMI backtrace for cpu 0 CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 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: 8832 Comm: kworker/u4:6 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 Workqueue: bat_events batadv_tt_purge RIP: 0010:mark_lock+0xa6/0x1160 kernel/locking/lockdep.c:3106 Code: 01 00 00 48 81 eb 50 01 00 00 48 81 c3 80 f5 d5 8c 48 8d 7b 30 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 04 0d 00 00 4c 89 e0 48 23 43 30 0f 84 ad 00 00 00 b8 01 00 RSP: 0018:ffff88809fca7a20 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff8cde4cf0 RCX: 1ffff110142229c7 RDX: 1ffffffff19bc9a4 RSI: ffff8880a1114e18 RDI: ffffffff8cde4d20 RBP: ffff8880a1114e18 R08: 000000000000065c R09: 0000000000000002 R10: ffff8880a1114e18 R11: 0000000000000000 R12: 0000000000000100 R13: ffff8880a1114540 R14: ffff8880a1114e38 R15: 0000000000000008 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000480 CR3: 000000009dcf1000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_acquire+0x6de/0x3ff0 kernel/locking/lockdep.c:3377 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2521 [inline] batadv_tt_purge+0x123/0xa00 net/batman-adv/translation-table.c:3812 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415