INFO: task syz-executor.1:12062 blocked for more than 143 seconds.
      Not tainted 5.10.0-rc4-next-20201120-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:28040 pid:12062 ppid:  8523 flags:0x00004002
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
 io_uring_cancel_files fs/io_uring.c:8735 [inline]
 io_uring_cancel_task_requests fs/io_uring.c:8787 [inline]
 __io_uring_files_cancel+0xc4d/0x14b0 fs/io_uring.c:8883
 io_uring_files_cancel include/linux/io_uring.h:51 [inline]
 exit_files+0xe4/0x170 fs/file.c:456
 do_exit+0xb61/0x29f0 kernel/exit.c:818
 do_group_exit+0x125/0x310 kernel/exit.c:920
 get_signal+0x3ea/0x1f70 kernel/signal.c:2750
 arch_do_signal_or_restart+0x2a6/0x1ea0 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:145 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:169 [inline]
 exit_to_user_mode_prepare+0x124/0x200 kernel/entry/common.c:199
 syscall_exit_to_user_mode+0x38/0x260 kernel/entry/common.c:274
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: Unable to access opcode bytes at RIP 0x45de8f.
RSP: 002b:00007fa831467cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000118bf28 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118bf28
RBP: 000000000118bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff752be8ef R14: 00007fa8314689c0 R15: 000000000118bf2c

Showing all locks held in the system:
1 lock held by khungtaskd/1650:
 #0: ffffffff8b339ca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6252
1 lock held by systemd-journal/4893:
1 lock held by in:imklog/8192:
 #0: ffff88801118a370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:932

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

NMI backtrace for cpu 1
CPU: 1 PID: 1650 Comm: khungtaskd Not tainted 5.10.0-rc4-next-20201120-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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 1261 Comm: kworker/u4:5 Not tainted 5.10.0-rc4-next-20201120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:match_held_lock+0x0/0x150 kernel/locking/lockdep.c:4889
Code: cc cc cc cc cc cc cc cc cc cc 0f 1f 44 00 00 48 8b 34 24 48 c7 c7 80 e7 49 89 e8 2e 02 c7 ff cc cc cc cc cc cc cc cc cc cc cc <48> 39 77 10 0f 84 97 00 00 00 66 f7 47 22 f0 ff 74 4b 48 83 ec 08
RSP: 0018:ffffc9000523fb48 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffffffff19daf73
RDX: 0000000000000000 RSI: ffffffff8b339be0 RDI: ffff88801398a3a8
RBP: ffffffff8b339be0 R08: 0000000000000000 R09: ffffffff8ced49cf
R10: fffffbfff19da939 R11: 0000000000000000 R12: ffff888013989a80
R13: ffff88801398a3a8 R14: 00000000ffffffff R15: ffff88801398a3a8
FS:  0000000000000000(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f896372a000 CR3: 0000000022195000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __lock_is_held kernel/locking/lockdep.c:5183 [inline]
 lock_is_held_type+0x7e/0x100 kernel/locking/lockdep.c:5474
 lock_is_held include/linux/lockdep.h:271 [inline]
 rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:123
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0x6a6/0x8c0 kernel/locking/lockdep.c:5406
 rcu_lock_acquire include/linux/rcupdate.h:255 [inline]
 rcu_read_lock include/linux/rcupdate.h:644 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline]
 batadv_nc_worker+0x12d/0xe50 net/batman-adv/network-coding.c:718
 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