INFO: task kworker/u4:2:59 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/u4:2    D25184    59      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
 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

Showing all locks held in the system:
3 locks held by kworker/u4:2/59:
 #0: 00000000edb0ac72 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
 #1: 00000000827da8e0 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
 #2: 00000000bb54ab08 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521
1 lock held by khungtaskd/1570:
 #0: 000000004c29940a (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by in:imklog/7810:
 #0: 000000000a46d1e4 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by kworker/1:3/9314:
 #0: 00000000991fb61b ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
 #1: 000000004969a8f8 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
3 locks held by syz-executor.5/20676:

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4684 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:___bpf_prog_run+0x3245/0x4e80 kernel/bpf/core.c:1233
Code: 8b 07 0f b6 d2 48 8d 54 d5 00 48 89 d1 48 c1 e9 03 80 3c 19 00 0f 85 f5 14 00 00 48 2b 02 49 83 c6 08 49 89 07 e9 fb cd ff ff <e8> 86 1c f6 ff 49 8d 7e 01 48 89 f8 48 89 fa 48 c1 e8 03 83 e2 07
RSP: 0018:ffff8880a171fa30 EFLAGS: 00000246
RAX: 1ffffffff10df6a1 RBX: dffffc0000000000 RCX: ffffffff816c48fe
RDX: 0000000000000000 RSI: 0000000000000015 RDI: ffffffff886fb508
RBP: ffff8880a171fb00 R08: 0000000000000000 R09: 0000000000000027
R10: 0000000000000006 R11: 0000000000000000 R12: ffffffff886fb460
R13: ffffed10142e3f62 R14: ffffc90001ad4078 R15: 0000000000000015
FS:  00007f7706c6d8c0(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7704280000 CR3: 00000000a15b3000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace: