------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(!test_bit(class_idx, lock_classes_in_use))
WARNING: CPU: 2 PID: 4120 at kernel/locking/lockdep.c:5207 __lock_acquire+0x13d5/0x1ce0 kernel/locking/lockdep.c:5207
Modules linked in:
CPU: 2 UID: 0 PID: 4120 Comm: syz.2.4893 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__lock_acquire+0x13d5/0x1ce0 kernel/locking/lockdep.c:5207
Code: 2a 80 7d 21 00 0f 88 09 fe ff ff 4c 8b 44 24 08 e9 b6 fc ff ff 90 48 c7 c6 20 1c 80 8d 48 c7 c7 7c bc 98 8d e8 fc 6f e2 ff 90 <0f> 0b 90 90 e9 c7 f0 ff ff e8 9d 7b 04 03 89 c3 e8 56 9f ff ff 85
RSP: 0018:ffffc900037e77f8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: ffff888025de5430 RCX: ffffffff8179a5b8
RDX: ffff888025de4900 RSI: ffffffff8179a5c5 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 000000002d2d2d2d R12: ffff888025de5480
R13: ffff888025de4900 R14: 0000000000000002 R15: 0000000000000003
FS:  00007f67024756c0(0000) GS:ffff8880d7060000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6702474f98 CR3: 000000005634c000 CR4: 0000000000352ef0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 down_write+0x92/0x200 kernel/locking/rwsem.c:1590
 kernfs_remove_by_name_ns+0x3d/0x110 fs/kernfs/dir.c:1712
 sysfs_remove_file include/linux/sysfs.h:770 [inline]
 driver_remove_file drivers/base/driver.c:201 [inline]
 driver_remove_file+0x4a/0x60 drivers/base/driver.c:197
 remove_bind_files drivers/base/bus.c:605 [inline]
 bus_remove_driver+0x224/0x2c0 drivers/base/bus.c:743
 driver_unregister+0x76/0xb0 drivers/base/driver.c:277
 comedi_device_detach_locked+0x12c/0xa50 drivers/comedi/drivers.c:207
 do_devconfig_ioctl+0x555/0x710 drivers/comedi/comedi_fops.c:848
 comedi_unlocked_ioctl+0x165d/0x2f00 drivers/comedi/comedi_fops.c:2178
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f670158eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6702475038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f67017e5fa0 RCX: 00007f670158eec9
RDX: 0000000000000000 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007f6701611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f67017e6038 R14: 00007f67017e5fa0 R15: 00007ffc8a221a98
 </TASK>