INFO: task io_uring-sq:32375 blocked for more than 143 seconds.
      Not tainted 5.10.0-rc1-next-20201030-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:io_uring-sq     state:D stack:30888 pid:32375 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3773 [inline]
 __schedule+0x893/0x2170 kernel/sched/core.c:4522
 schedule+0xcf/0x270 kernel/sched/core.c:4600
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4659
 kthread+0x2a6/0x4a0 kernel/kthread.c:285
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Showing all locks held in the system:
4 locks held by kworker/u4:0/8:
1 lock held by khungtaskd/1652:
 #0: ffffffff8b337f60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6253
1 lock held by in:imklog/8178:
 #0: ffff88801c1dcff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932
4 locks held by kworker/0:5/14924:
 #0: ffff8880b9e34d18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline]
 #0: ffff8880b9e34d18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x21a/0x2170 kernel/sched/core.c:4440
 #1: ffff8880b9e1ff88 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833
 #2: ffff8880b9e246d8 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x5a/0x1f0 kernel/time/timer.c:944
 #3: ffffffff8f19f758 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_active_state lib/debugobjects.c:922 [inline]
 #3: ffffffff8f19f758 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_active_state+0x10b/0x350 lib/debugobjects.c:909
5 locks held by kworker/1:2/825:
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888014f33d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243
 #1: ffffc9001c197da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247
 #2: ffff888144afa218 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:731 [inline]
 #2: ffff888144afa218 (&dev->mutex){....}-{3:3}, at: hub_event+0x1c5/0x42d0 drivers/usb/core/hub.c:5537
 #3: ffff888144afe588 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3030 [inline]
 #3: ffff888144afe588 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5154 [inline]
 #3: ffff888144afe588 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
 #3: ffff888144afe588 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5509 [inline]
 #3: ffff888144afe588 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x216c/0x42d0 drivers/usb/core/hub.c:5591
 #4: ffff888144a95e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_init+0x1b2/0x2dd0 drivers/usb/core/hub.c:4582
1 lock held by syz-executor.4/9399:
 #0: ffffffff8c918390 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1816
1 lock held by syz-executor.4/9403:
 #0: ffffffff8c918390 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1816

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

NMI backtrace for cpu 1
CPU: 1 PID: 1652 Comm: khungtaskd Not tainted 5.10.0-rc1-next-20201030-syzkaller #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+0x107/0x163 lib/dump_stack.c:118
 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:147 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline]
 watchdog+0xd89/0xf30 kernel/hung_task.c:338
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8 Comm: kworker/u4:0 Not tainted 5.10.0-rc1-next-20201030-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:__lock_acquire+0x221/0x5590 kernel/locking/lockdep.c:4765
Code: 00 3b 4c 24 10 75 0c 48 83 7c 24 18 00 0f 85 9d 0c 00 00 48 8b 44 24 30 0f b7 4c 24 10 4a 8d 2c 10 48 8d 45 20 66 81 e1 ff 1f <48> 89 c2 48 89 44 24 28 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03
RSP: 0018:ffffc90000cd7918 EFLAGS: 00000002
RAX: ffff888010d35930 RBX: 0000000000000000 RCX: 000000000000002c
RDX: 0000000000000003 RSI: 1ffff110021a6b21 RDI: ffff888010d35908
RBP: ffff888010d35910 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000078 R11: 0000000000000000 R12: ffff888010d34f80
R13: 0000000000000000 R14: ffffffff8b337f60 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561156abf180 CR3: 0000000064f3f000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire kernel/locking/lockdep.c:5436 [inline]
 lock_acquire+0x1af/0x8b0 kernel/locking/lockdep.c:5401
 rcu_lock_acquire include/linux/rcupdate.h:248 [inline]
 rcu_read_lock include/linux/rcupdate.h:641 [inline]
 inet_twsk_purge+0x112/0x7c0 net/ipv4/inet_timewait_sock.c:268
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:190
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:604
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296