============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/0:2/186 is trying to acquire lock:
ffff888031256128 (&grp->list_lock){.+.+}-{3:3}, at: __deliver_to_subscribers sound/core/seq/seq_clientmgr.c:723 [inline]
ffff888031256128 (&grp->list_lock){.+.+}-{3:3}, at: deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
ffff888031256128 (&grp->list_lock){.+.+}-{3:3}, at: snd_seq_deliver_event+0x241/0xa40 sound/core/seq/seq_clientmgr.c:813

but task is already holding lock:
ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: __deliver_to_subscribers sound/core/seq/seq_clientmgr.c:723 [inline]
ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: snd_seq_deliver_event+0x241/0xa40 sound/core/seq/seq_clientmgr.c:813

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

       CPU0
       ----
  lock(&grp->list_lock);
  lock(&grp->list_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by kworker/0:2/186:
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801b02b140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc9000308fc40 ((work_completion)(&runtime->event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc9000308fc40 ((work_completion)(&runtime->event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: __deliver_to_subscribers sound/core/seq/seq_clientmgr.c:723 [inline]
 #2: ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
 #2: ffff88802a0a0928 (&grp->list_lock){.+.+}-{3:3}, at: snd_seq_deliver_event+0x241/0xa40 sound/core/seq/seq_clientmgr.c:813

stack backtrace:
CPU: 0 UID: 0 PID: 186 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events snd_rawmidi_input_event_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x24df/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __raw_read_lock include/linux/rwlock_api_smp.h:163 [inline]
 _raw_read_lock+0x36/0x50 kernel/locking/spinlock.c:232
 __deliver_to_subscribers sound/core/seq/seq_clientmgr.c:723 [inline]
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
 snd_seq_deliver_event+0x241/0xa40 sound/core/seq/seq_clientmgr.c:813
 snd_seq_kernel_client_dispatch+0x201/0x310 sound/core/seq/seq_clientmgr.c:2439
 queue_broadcast_event sound/core/seq/seq_queue.c:585 [inline]
 snd_seq_queue_process_event sound/core/seq/seq_queue.c:601 [inline]
 snd_seq_control_queue+0x977/0x11b0 sound/core/seq/seq_queue.c:659
 __snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:626 [inline]
 _snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:672 [inline]
 snd_seq_deliver_single_event+0x568/0xc40 sound/core/seq/seq_clientmgr.c:687
 snd_seq_deliver_event+0x26a/0xa40 sound/core/seq/seq_clientmgr.c:815
 snd_seq_kernel_client_dispatch+0x201/0x310 sound/core/seq/seq_clientmgr.c:2439
 send_timer_event sound/core/seq/oss/seq_oss_timer.c:140 [inline]
 snd_seq_oss_timer_start+0x336/0x580 sound/core/seq/oss/seq_oss_timer.c:161
 send_midi_event sound/core/seq/oss/seq_oss_midi.c:576 [inline]
 snd_seq_oss_midi_input+0x332/0x9c0 sound/core/seq/oss/seq_oss_midi.c:501
 __snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:626 [inline]
 _snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:672 [inline]
 snd_seq_deliver_single_event+0x568/0xc40 sound/core/seq/seq_clientmgr.c:687
 __deliver_to_subscribers sound/core/seq/seq_clientmgr.c:735 [inline]
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
 snd_seq_deliver_event+0x543/0xa40 sound/core/seq/seq_clientmgr.c:813
 snd_seq_kernel_client_dispatch+0x201/0x310 sound/core/seq/seq_clientmgr.c:2439
 snd_midi_input_event+0x2b1/0x400 sound/core/seq/seq_midi.c:93
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>