INFO: task iou-sqp-31544:31545 blocked for more than 143 seconds.
      Not tainted 5.12.0-rc7-next-20210415-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:iou-sqp-31544   state:D stack:29688 pid:31545 ppid:  8463 flags:0x00004004
Call Trace:
 context_switch kernel/sched/core.c:4329 [inline]
 __schedule+0x917/0x2170 kernel/sched/core.c:5079
 schedule+0xcf/0x270 kernel/sched/core.c:5158
 __io_uring_cancel+0x285/0x420 fs/io_uring.c:8977
 io_uring_files_cancel include/linux/io_uring.h:16 [inline]
 do_exit+0x299/0x2a70 kernel/exit.c:780
 io_sq_thread+0x60a/0x1340 fs/io_uring.c:6873
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Showing all locks held in the system:
2 locks held by kworker/u4:1/25:
 #0: ffff8880b9c35318 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x7fe/0xe70 kernel/sched/fair.c:10664
 #1: ffffc90000dffda8 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250
1 lock held by khungtaskd/1648:
 #0: ffffffff8bf76560 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6333

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

NMI backtrace for cpu 1
CPU: 1 PID: 1648 Comm: khungtaskd Not tainted 5.12.0-rc7-next-20210415-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+0x141/0x1d7 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:253 [inline]
 watchdog+0xd3b/0xf50 kernel/hung_task.c:338
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 25 Comm: kworker/u4:1 Not tainted 5.12.0-rc7-next-20210415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__lock_release kernel/locking/lockdep.c:5175 [inline]
RIP: 0010:lock_release+0x1c3/0x720 kernel/locking/lockdep.c:5532
Code: 8b 05 ed 2e 6e 0c 85 c0 0f 84 08 02 00 00 4d 8d b7 f0 09 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 0f b6 04 02 <84> c0 74 08 3c 03 0f 8e b9 04 00 00 45 8b af f0 09 00 00 45 85 ed
RSP: 0018:ffffc90000dffb48 EFLAGS: 00000802
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000000001
RDX: 1ffff1100240885e RSI: 0000000000000201 RDI: 0000000000000000
RBP: 1ffff920001bff6b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888019cbd218
R13: ffff88801daa0c00 R14: ffff8880120442f0 R15: ffff888012043900
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f09d7842000 CR3: 0000000029729000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline]
 _raw_spin_unlock_bh+0x12/0x30 kernel/locking/spinlock.c:207
 spin_unlock_bh include/linux/spinlock.h:404 [inline]
 batadv_nc_purge_paths+0x2a5/0x3a0 net/batman-adv/network-coding.c:467
 batadv_nc_worker+0x836/0xe50 net/batman-adv/network-coding.c:718
 process_one_work+0x98d/0x1600 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:294