============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G             L     
--------------------------------------------
syz.1.2475/13294 is trying to acquire lock:
ffff8881750808f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_do_insn+0x38/0x3d0

but task is already holding lock:
ffff8881750820f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x210/0x1af0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&dev->mutex#4);
  lock(&dev->mutex#4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz.1.2475/13294:
 #0: ffff8881750820f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x210/0x1af0

stack backtrace:
CPU: 1 UID: 0 PID: 13294 Comm: syz.1.2475 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_deadlock_bug+0x279/0x290
 __lock_acquire+0x253f/0x2cf0
 lock_acquire+0xf0/0x2e0
 __mutex_lock+0x19f/0x1300
 comedi_do_insn+0x38/0x3d0
 comedi_dio_bitfield2+0x301/0x3e0
 bonding_dio_insn_bits+0x2cc/0x5e0
 insn_rw_emulate_bits+0x363/0x620
 parse_insn+0xa3e/0x1b20
 do_insn_ioctl+0x174/0x5a0
 comedi_unlocked_ioctl+0xe06/0x1af0
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f47a719c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f47a7f9c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f47a7415fa0 RCX: 00007f47a719c819
RDX: 0000200000000000 RSI: 000000008028640c RDI: 0000000000000003
RBP: 00007f47a7232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f47a7416038 R14: 00007f47a7415fa0 R15: 00007ffe33957478
 </TASK>
