syzbot

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BUG: KCSAN: data-race in __snd_rawmidi_transmit_ack / snd_rawmidi_drain_output

write to 0xffff88809c5e7db8 of 8 bytes by task 3441 on cpu 0:
 __snd_rawmidi_transmit_ack+0xcc/0x1c0 sound/core/rawmidi.c:1234
 snd_rawmidi_transmit+0x8c/0xc0 sound/core/rawmidi.c:1293
 snd_vmidi_output_work+0xaf/0x1f0 sound/core/seq/seq_virmidi.c:144
 process_one_work+0x424/0x930 kernel/workqueue.c:2268
 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2414
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff88809c5e7db8 of 8 bytes by task 16414 on cpu 1:
 snd_rawmidi_drain_output+0x1e9/0x310 sound/core/rawmidi.c:211
 close_substream.part.0+0x1f2/0x310 sound/core/rawmidi.c:499
 close_substream sound/core/rawmidi.c:485 [inline]
 rawmidi_release_priv+0x11a/0x180 sound/core/rawmidi.c:525
 snd_rawmidi_release+0x3f/0x90 sound/core/rawmidi.c:556
 __fput+0x1e9/0x500 fs/file_table.c:280
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16414 Comm: syz-executor.3 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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