syzbot

================================
WARNING: inconsistent lock state
syzkaller #0 Tainted: G             L     
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
syz.6.5949/31470 [HC0[0]:SC0[2]:HE1:SE0] takes:
ffff888031eb1868 (&dev->spinlock){?.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
ffff888031eb1868 (&dev->spinlock){?.-.}-{3:3}, at: waveform_ao_cancel+0x8d/0x120 drivers/comedi/drivers/comedi_test.c:628
{IN-HARDIRQ-W} state was registered at:
  lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
  __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
  _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
  spin_lock include/linux/spinlock.h:341 [inline]
  das16m1_interrupt+0x5e/0x180 drivers/comedi/drivers/das16m1.c:460
  __handle_irq_event_percpu+0x227/0x9e0 kernel/irq/handle.c:209
  handle_irq_event_percpu kernel/irq/handle.c:246 [inline]
  handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:263
  handle_edge_irq+0x23b/0xa10 kernel/irq/chip.c:855
  generic_handle_irq_desc include/linux/irqdesc.h:186 [inline]
  handle_irq arch/x86/kernel/irq.c:262 [inline]
  call_irq_handler arch/x86/kernel/irq.c:-1 [inline]
  __common_interrupt+0x141/0x1f0 arch/x86/kernel/irq.c:333
  common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:326
  asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
  __preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
  rcu_is_watching+0x10/0xb0 kernel/rcu/tree.c:751
  rcu_read_unlock include/linux/rcupdate.h:879 [inline]
  class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
  unwind_next_frame+0x1a66/0x23c0 arch/x86/kernel/unwind_orc.c:695
  arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
  stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  unpoison_slab_object mm/kasan/common.c:340 [inline]
  __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
  kasan_slab_alloc include/linux/kasan.h:253 [inline]
  slab_post_alloc_hook mm/slub.c:4501 [inline]
  slab_alloc_node mm/slub.c:4830 [inline]
  kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4837
  alloc_empty_file+0x55/0x1d0 fs/file_table.c:237
  path_openat+0x10f/0x3860 fs/namei.c:4816
  do_file_open+0x23e/0x4a0 fs/namei.c:4859
  do_sys_openat2+0x113/0x200 fs/open.c:1366
  do_sys_open fs/open.c:1372 [inline]
  __do_sys_openat fs/open.c:1388 [inline]
  __se_sys_openat fs/open.c:1383 [inline]
  __x64_sys_openat+0x138/0x170 fs/open.c:1383
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
  entry_SYSCALL_64_after_hwframe+0x77/0x7f
irq event stamp: 5590
hardirqs last  enabled at (5589): [<ffffffff8bbd8070>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
hardirqs last  enabled at (5589): [<ffffffff8bbd8070>] _raw_spin_unlock_irqrestore+0x30/0x80 kernel/locking/spinlock.c:194
hardirqs last disabled at (5588): [<ffffffff8bbd7eca>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
hardirqs last disabled at (5588): [<ffffffff8bbd7eca>] _raw_spin_lock_irqsave+0x1a/0x60 kernel/locking/spinlock.c:162
softirqs last  enabled at (5542): [<ffffffff8aa0f52f>] nr_release+0x20f/0x450 net/netrom/af_netrom.c:558
softirqs last disabled at (5590): [<ffffffff8910d5ed>] spin_lock_bh include/linux/spinlock.h:347 [inline]
softirqs last disabled at (5590): [<ffffffff8910d5ed>] waveform_ao_cancel+0x8d/0x120 drivers/comedi/drivers/comedi_test.c:628

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

       CPU0
       ----
  lock(&dev->spinlock);
  <Interrupt>
    lock(&dev->spinlock);

 *** DEADLOCK ***

1 lock held by syz.6.5949/31470:
 #0: ffff888031eb18f8 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_close+0x70/0x5e0 drivers/comedi/comedi_fops.c:3029

stack backtrace:
CPU: 1 UID: 0 PID: 31470 Comm: syz.6.5949 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_usage_bug+0x28b/0x2e0 kernel/locking/lockdep.c:4042
 valid_state kernel/locking/lockdep.c:4056 [inline]
 mark_lock_irq+0x410/0x420 kernel/locking/lockdep.c:-1
 mark_lock+0x115/0x190 kernel/locking/lockdep.c:4753
 mark_usage kernel/locking/lockdep.c:4662 [inline]
 __lock_acquire+0x9d0/0x2cf0 kernel/locking/lockdep.c:5191
 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178
 spin_lock_bh include/linux/spinlock.h:347 [inline]
 waveform_ao_cancel+0x8d/0x120 drivers/comedi/drivers/comedi_test.c:628
 do_cancel drivers/comedi/comedi_fops.c:818 [inline]
 comedi_close+0x27e/0x5e0 drivers/comedi/comedi_fops.c:3036
 __fput+0x44f/0xa70 fs/file_table.c:469
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x69b/0x2320 kernel/exit.c:971
 __do_sys_exit kernel/exit.c:1079 [inline]
 __se_sys_exit kernel/exit.c:1077 [inline]
 __x64_sys_exit+0x40/0x40 kernel/exit.c:1077
 x64_sys_call+0x2231/0x2240 arch/x86/include/generated/asm/syscalls_64.h:61
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f76f4b9c629
Code: Unable to access opcode bytes at 0x7f76f4b9c5ff.
RSP: 002b:00007f76f5acafd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007f76f4e16090 RCX: 00007f76f4b9c629
RDX: 00007f76f5acb9c8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f76f4c32b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f76f4e16128 R14: 00007f76f4e16090 R15: 00007ffe72fef4b8
 </TASK>