============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.0.17/6573 is trying to acquire lock: ffff88807aeceb30 (&chip->mutex){+.+.}-{3:3}, at: snd_usb_endpoint_close+0x3c/0x4c0 sound/usb/endpoint.c:964 but task is already holding lock: ffff88807aeceb30 (&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.0.17/6573: #0: ffff88802bb274e0 (&runtime->oss.params_lock){+.+.}-{3:3}, at: snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1411 [inline] #0: ffff88802bb274e0 (&runtime->oss.params_lock){+.+.}-{3:3}, at: snd_pcm_oss_write+0x293/0x1120 sound/core/oss/pcm_oss.c:2810 #1: ffff88802bb27238 (&runtime->buffer_mutex){+.+.}-{3:3}, at: snd_pcm_buffer_access_lock sound/core/pcm_native.c:696 [inline] #1: ffff88802bb27238 (&runtime->buffer_mutex){+.+.}-{3:3}, at: snd_pcm_hw_params+0x15a/0x1c50 sound/core/pcm_native.c:735 #2: ffff88807aeceb30 (&chip->mutex){+.+.}-{3:3}, at: snd_usb_endpoint_set_params+0x6d/0x2b50 sound/usb/endpoint.c:1362 stack backtrace: CPU: 1 PID: 6573 Comm: syz.0.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: 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_write1 sound/core/oss/pcm_oss.c:1415 [inline] snd_pcm_oss_write+0x2ff/0x1120 sound/core/oss/pcm_oss.c:2810 vfs_write+0x288/0x940 fs/read_write.c:582 ksys_write+0x147/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f333838f749 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:00007f3339238038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f33385e5fa0 RCX: 00007f333838f749 RDX: 00000000000005ce RSI: 0000200000000640 RDI: 0000000000000004 RBP: 00007f3338413f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f33385e6038 R14: 00007f33385e5fa0 R15: 00007fff5c678bb8