============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G             L     
--------------------------------------------
syz.7.1247/10398 is trying to acquire lock:
ffff888065aca160 (&rmidi->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
ffff888065aca160 (&rmidi->open_mutex){+.+.}-{4:4}, at: rawmidi_release_priv+0x45/0x280 sound/core/rawmidi.c:574

but task is already holding lock:
ffff88802e681960 (&rmidi->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
ffff88802e681960 (&rmidi->open_mutex){+.+.}-{4:4}, at: rawmidi_release_priv+0x45/0x280 sound/core/rawmidi.c:574

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

       CPU0
       ----
  lock(&rmidi->open_mutex);
  lock(&rmidi->open_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

locks held by syz.7.1247/10398: 2, last CPU#0:
 #0: ffff88802e681960 (&rmidi->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #0: ffff88802e681960 (&rmidi->open_mutex){+.+.}-{4:4}, at: rawmidi_release_priv+0x45/0x280 sound/core/rawmidi.c:574
 #1: ffff888065aca460 (&ump->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #1: ffff888065aca460 (&ump->open_mutex){+.+.}-{4:4}, at: snd_ump_legacy_close+0x117/0x300 sound/core/ump.c:1182

stack backtrace:
CPU: 0 UID: 0 PID: 10398 Comm: syz.7.1247 Tainted: G             L      syzkaller #0 PREEMPT(lazy) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3057
 check_deadlock kernel/locking/lockdep.c:3109 [inline]
 validate_chain kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x1343/0x1ec0 kernel/locking/lockdep.c:5253
 lock_acquire kernel/locking/lockdep.c:5886 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1bc0 kernel/locking/mutex.c:821
 class_mutex_constructor include/linux/mutex.h:253 [inline]
 rawmidi_release_priv+0x45/0x280 sound/core/rawmidi.c:574
 snd_rawmidi_kernel_release+0x3a/0xd0 sound/core/rawmidi.c:596
 snd_ump_legacy_close+0x234/0x300 sound/core/ump.c:1187
 close_substream.part.0+0x16b/0x860 sound/core/rawmidi.c:560
 close_substream include/linux/mutex.h:253 [inline]
 rawmidi_release_priv+0x210/0x280 sound/core/rawmidi.c:580
 snd_rawmidi_release+0x5a/0xf0 sound/core/rawmidi.c:610
 __fput+0x3ff/0xb50 fs/file_table.c:512
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x951/0x2ae0 kernel/exit.c:1008
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1151
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
 do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd48f39e0d9
Code: Unable to access opcode bytes at 0x7fd48f39e0af.
RSP: 002b:00007fd4902120e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 00007fd48f625fa8 RCX: 00007fd48f39e0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd48f625fa8
RBP: 00007fd48f625fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd48f626038 R14: 00007fff220f5850 R15: 00007fff220f5938
 </TASK>