syzbot

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BUG: KCSAN: data-race in snd_seq_cell_alloc.isra.0 / snd_seq_info_pool

read to 0xffff888079da68b0 of 4 bytes by task 13797 on cpu 1:
 snd_seq_info_pool+0xdf/0x170 sound/core/seq/seq_memory.c:500
 snd_seq_info_clients_read+0x3b8/0x4a0 sound/core/seq/seq_clientmgr.c:2473
 snd_info_seq_show+0x85/0xb0 sound/core/info.c:363
 seq_read+0x350/0x9d0 fs/seq_file.c:229
 proc_reg_read+0xe9/0x140 fs/proc/inode.c:223
 do_loop_readv_writev fs/read_write.c:714 [inline]
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_iter_read+0x357/0x3d0 fs/read_write.c:935
 vfs_readv+0x9c/0xf0 fs/read_write.c:997
 do_preadv+0x131/0x1d0 fs/read_write.c:1089
 __do_sys_preadv fs/read_write.c:1139 [inline]
 __se_sys_preadv fs/read_write.c:1134 [inline]
 __x64_sys_preadv+0x61/0x80 fs/read_write.c:1134
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888079da68b0 of 4 bytes by task 13811 on cpu 0:
 snd_seq_cell_alloc.isra.0+0x326/0x3c0 sound/core/seq/seq_memory.c:260
 snd_seq_event_dup+0x103/0x590 sound/core/seq/seq_memory.c:298
 snd_seq_client_enqueue_event.constprop.0+0x157/0x2a0 sound/core/seq/seq_clientmgr.c:968
 snd_seq_write+0x23f/0x4d0 sound/core/seq/seq_clientmgr.c:1093
 __vfs_write+0x67/0xc0 fs/read_write.c:494
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0x17b/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13811 Comm: syz-executor.2 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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