syzbot

============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.17/5943 is trying to acquire lock:
ffff88802cb04b30 (&chip->mutex){+.+.}-{3:3}, at: snd_usb_endpoint_close+0x3c/0x4c0 sound/usb/endpoint.c:964

but task is already holding lock:
ffff88802cb04b30 (&chip->mutex){+.+.}-{3:3}, at: snd_usb_endpoint_set_params+0x6d/0x2b50 sound/usb/endpoint.c:1362

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

       CPU0
       ----
  lock(&chip->mutex);
  lock(&chip->mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by syz.0.17/5943:
 #0: ffff88802383b4e0 (&runtime->oss.params_lock){+.+.}-{3:3}, at: snd_pcm_oss_sync+0x2a7/0xc20 sound/core/oss/pcm_oss.c:1675
 #1: ffff88802383b238 (&runtime->buffer_mutex){+.+.}-{3:3}, at: snd_pcm_buffer_access_lock sound/core/pcm_native.c:696 [inline]
 #1: ffff88802383b238 (&runtime->buffer_mutex){+.+.}-{3:3}, at: snd_pcm_hw_params+0x15a/0x1c50 sound/core/pcm_native.c:735
 #2: ffff88802cb04b30 (&chip->mutex){+.+.}-{3:3}, at: snd_usb_endpoint_set_params+0x6d/0x2b50 sound/usb/endpoint.c:1362

stack backtrace:
CPU: 0 PID: 5943 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain kernel/locking/lockdep.c:3856 [inline]
 __lock_acquire+0x5d40/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
 snd_usb_endpoint_close+0x3c/0x4c0 sound/usb/endpoint.c:964
 close_endpoints sound/usb/pcm.c:454 [inline]
 snd_usb_hw_params+0x1357/0x19c0 sound/usb/pcm.c:573
 snd_pcm_hw_params+0x835/0x1c50 sound/core/pcm_native.c:779
 snd_pcm_oss_change_params_locked+0x2144/0x3d30 sound/core/oss/pcm_oss.c:976
 snd_pcm_oss_make_ready_locked sound/core/oss/pcm_oss.c:1197 [inline]
 snd_pcm_oss_sync+0x363/0xc20 sound/core/oss/pcm_oss.c:1679
 snd_pcm_oss_release+0x102/0x240 sound/core/oss/pcm_oss.c:2589
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd25f18f749
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:00007ffc9d0a8818 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000194ff RCX: 00007fd25f18f749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 000000029d0a8b0f
R10: 0000001b2c620000 R11: 0000000000000246 R12: 00007fd25f3e5fac
R13: 00007fd25f3e5fa0 R14: ffffffffffffffff R15: 0000000000000003
 </TASK>