INFO: task kworker/u4:6:9934 blocked for more than 143 seconds.
      Not tainted 5.10.0-rc4-next-20201117-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:24856 pid: 9934 ppid:     2 flags:0x00004000
Workqueue: events_unbound io_ring_exit_work
Call Trace:
 context_switch kernel/sched/core.c:4269 [inline]
 __schedule+0x890/0x2030 kernel/sched/core.c:5019
 schedule+0xcf/0x270 kernel/sched/core.c:5098
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1847
 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_stop+0x17a/0x720 kernel/kthread.c:596
 io_put_sq_data fs/io_uring.c:7235 [inline]
 io_sq_thread_stop+0x452/0x570 fs/io_uring.c:7332
 io_finish_async fs/io_uring.c:7339 [inline]
 io_ring_ctx_free fs/io_uring.c:8494 [inline]
 io_ring_exit_work+0x102/0x7a0 fs/io_uring.c:8588
 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

Showing all locks held in the system:
1 lock held by khungtaskd/1651:
 #0: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6252
2 locks held by systemd-journal/4896:
1 lock held by in:imklog/8187:
2 locks held by kworker/u4:6/9934:
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff888010069138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x821/0x15a0 kernel/workqueue.c:2243
 #1: ffffc900168ffda8 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x854/0x15a0 kernel/workqueue.c:2247
3 locks held by kworker/u4:7/9962:
1 lock held by syz-executor.4/20068:
 #0: ffff88805092f1a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1583 [inline]
 #0: ffff88805092f1a0 (sk_lock-AF_INET6){+.+.}-{0:0}, at: mptcp_stream_connect+0x85/0x800 net/mptcp/protocol.c:2722

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

NMI backtrace for cpu 0
CPU: 0 PID: 1651 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201117-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: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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22785 Comm: kworker/u4:8 Not tainted 5.10.0-rc4-next-20201117-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: phy11 ieee80211_iface_work
RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:416 [inline]
RIP: 0010:__lock_acquire+0xc3d/0x5c00 kernel/locking/lockdep.c:4818
Code: 3c 02 00 0f 85 14 4b 00 00 48 83 7b 40 00 0f 84 f3 0d 00 00 0f b7 44 24 38 8b 4c 24 58 8b 5c 24 50 c1 e0 0d 66 0b 44 24 08 98 <2b> 44 24 60 33 44 24 48 89 c2 29 c1 01 d8 c1 c2 06 31 ca 89 d1 29
RSP: 0018:ffffc90015f1f3a0 EFLAGS: 00000002
RAX: 0000000000000732 RBX: 000000009ea907f8 RCX: 000000000e6a5fe7
RDX: 1ffffffff1d82e28 RSI: 0000000000000008 RDI: ffffffff8ec17140
RBP: ffff888147c49a80 R08: 0000000000000000 R09: ffffffff8ebc0847
R10: fffffbfff1d78108 R11: 0000000000000000 R12: ffff888147c4a420
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000074b698 CR3: 000000001259a000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire kernel/locking/lockdep.c:5435 [inline]
 lock_acquire+0x2a3/0x8c0 kernel/locking/lockdep.c:5400
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 cfg80211_put_bss+0x3c/0x270 net/wireless/scan.c:2496
 ieee80211_rx_bss_put net/mac80211/scan.c:37 [inline]
 ieee80211_rx_bss_put+0x3f/0x50 net/mac80211/scan.c:32
 ieee80211_rx_bss_info net/mac80211/ibss.c:1198 [inline]
 ieee80211_rx_mgmt_probe_beacon+0xd83/0x1690 net/mac80211/ibss.c:1615
 ieee80211_ibss_rx_queued_mgmt+0xe3e/0x1870 net/mac80211/ibss.c:1642
 ieee80211_iface_work+0x7ed/0xa90 net/mac80211/iface.c:1421
 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