INFO: task kworker/u4:0:8 blocked for more than 143 seconds.
      Not tainted 5.11.0-rc5-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:24928 pid:    8 ppid:     2 flags:0x00004000
Workqueue: events_unbound io_ring_exit_work
Call Trace:
 context_switch kernel/sched/core.c:4327 [inline]
 __schedule+0x90c/0x21a0 kernel/sched/core.c:5078
 schedule+0xcf/0x270 kernel/sched/core.c:5157
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1854
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
 kthread_park+0x122/0x1b0 kernel/kthread.c:582
 io_sq_thread_park fs/io_uring.c:7462 [inline]
 io_sq_thread_park fs/io_uring.c:7456 [inline]
 io_sq_thread_stop+0xfe/0x570 fs/io_uring.c:7480
 io_finish_async fs/io_uring.c:7498 [inline]
 io_ring_ctx_free fs/io_uring.c:8663 [inline]
 io_ring_exit_work+0x62/0x6d0 fs/io_uring.c:8756
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Showing all locks held in the system:
3 locks held by kworker/u4:0/8:
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888010071138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x871/0x15f0 kernel/workqueue.c:2246
 #1: ffffc90000cefda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x15f0 kernel/workqueue.c:2250
 #2: ffff8880312d8c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7461 [inline]
 #2: ffff8880312d8c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_park fs/io_uring.c:7456 [inline]
 #2: ffff8880312d8c70 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread_stop+0xd6/0x570 fs/io_uring.c:7480
4 locks held by kworker/u4:3/88:
1 lock held by khungtaskd/1645:
 #0: ffffffff8b373ce0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6259
1 lock held by in:imklog/8357:
 #0: ffff88801284a130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:947
2 locks held by agetty/8362:
 #0: ffff88801e68f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266
 #1: ffffc900016d42e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x21d/0x1aa0 drivers/tty/n_tty.c:2155
2 locks held by kworker/u4:7/14111:
1 lock held by syz-executor.4/17503:
 #0: ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5550
1 lock held by syz-executor.3/17538:
 #0: 
ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5550
1 lock held by syz-executor.0/17540:
 #0: ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8ca5b6e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5550

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

NMI backtrace for cpu 0
CPU: 0 PID: 1645 Comm: khungtaskd Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd43/0xfa0 kernel/hung_task.c:294
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 88 Comm: kworker/u4:3 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:__kasan_check_read+0x4/0x10 mm/kasan/shadow.c:30
Code: 05 07 48 85 db 0f 85 55 95 06 07 48 83 c4 60 5b 5d 41 5c 41 5d c3 c3 e9 55 96 06 07 cc cc cc cc cc cc cc cc cc cc 48 8b 0c 24 <89> f6 31 d2 e9 63 f9 ff ff 0f 1f 00 48 8b 0c 24 89 f6 ba 01 00 00
RSP: 0018:ffffc90000f476b8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff8158bcf1
RDX: ffff888011476180 RSI: 0000000000000008 RDI: ffffffff8d03ae08
RBP: 1ffff920001e8eda R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8737fbf8 R11: 0000000000000000 R12: ffffffff8b072bd8
R13: 0000000000008785 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc167fb0010 CR3: 000000001a2de000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 cpumask_test_cpu include/linux/cpumask.h:373 [inline]
 trace_lock_release include/trace/events/lock.h:58 [inline]
 lock_release+0xa1/0x710 kernel/locking/lockdep.c:5453
 __raw_spin_unlock include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:183
 spin_unlock include/linux/spinlock.h:394 [inline]
 get_next_corpse net/netfilter/nf_conntrack_core.c:2220 [inline]
 nf_ct_iterate_cleanup+0x109/0x400 net/netfilter/nf_conntrack_core.c:2244
 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2329 [inline]
 nf_ct_iterate_cleanup_net+0x113/0x170 net/netfilter/nf_conntrack_core.c:2314
 masq_device_event+0xae/0xe0 net/netfilter/nf_nat_masquerade.c:88
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2040
 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline]
 call_netdevice_notifiers net/core/dev.c:2066 [inline]
 dev_close_many+0x30b/0x650 net/core/dev.c:1641
 rollback_registered_many+0x3ee/0x14c0 net/core/dev.c:9472
 unregister_netdevice_many.part.0+0x1a/0x2f0 net/core/dev.c:10735
 unregister_netdevice_many+0x36/0x50 net/core/dev.c:10734
 ip6gre_exit_batch_net+0x511/0x750 net/ipv6/ip6_gre.c:1630
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604
 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296