comedi comedi0: comedi_test: 1000000 microvolt, 100000 microsecond waveform attached
comedi comedi1: comedi_bond: 0:2  attached, 32 channels from 1 devices
============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz-executor274/5633 is trying to acquire lock:
ffff8880308dc0f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_do_insn+0x38/0x3d0 drivers/comedi/kcomedilib/kcomedilib_main.c:183

but task is already holding lock:
ffff888030d4f8f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x210/0x1af0 drivers/comedi/comedi_fops.c:2290

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

locks held by syz-executor274/5633: 1, last CPU#1:
 #0: ffff888030d4f8f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x210/0x1af0 drivers/comedi/comedi_fops.c:2290

stack backtrace:
CPU: 1 UID: 0 PID: 5633 Comm: syz-executor274 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x27a/0x290 kernel/locking/lockdep.c:3085
 check_deadlock kernel/locking/lockdep.c:3137 [inline]
 validate_chain kernel/locking/lockdep.c:3939 [inline]
 __lock_acquire+0x25db/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
 comedi_do_insn+0x38/0x3d0 drivers/comedi/kcomedilib/kcomedilib_main.c:183
 comedi_dio_bitfield2+0x2fc/0x3d0 drivers/comedi/kcomedilib/kcomedilib_main.c:314
 bonding_dio_insn_bits+0x2cc/0x5e0 drivers/comedi/drivers/comedi_bond.c:100
 parse_insn+0xe75/0x1b20 drivers/comedi/comedi_fops.c:1613
 do_insn_ioctl+0x17c/0x5b0 drivers/comedi/comedi_fops.c:1790
 comedi_unlocked_ioctl+0xe06/0x1af0 drivers/comedi/comedi_fops.c:2422
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6ed6c56c9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff5439bf48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc6ed6c56c9
RDX: 0000200000000400 RSI: 000000008028640c RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 431bde82d7b634db R14: 00007fc6ed758c40 R15: 0000000000000002
 </TASK>