KCSAN: data-race in __snd_pcm_lib_xfer / snd_pcm_oss_set_trigger

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: eccc8767 Merge branch 'fixes' of git://git.kernel.org/pub/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146cf114500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=61bda0a82650e7ed14ef
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [alsa-...@alsa-project.org daniel....@oracle.com gusta...@kernel.org linux-...@vger.kernel.org pe...@perex.cz ti...@suse.com vba...@suse.cz wal...@google.com]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+61bda0...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __snd_pcm_lib_xfer / snd_pcm_oss_set_trigger

write to 0xffff88802a6780b8 of 8 bytes by task 17941 on cpu 1:
snd_pcm_oss_set_trigger+0x437/0x490 sound/core/oss/pcm_oss.c:2062
snd_pcm_oss_ioctl+0xce8/0x2900 sound/core/oss/pcm_oss.c:2680
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
__x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88802a6780b8 of 8 bytes by task 17935 on cpu 0:
__snd_pcm_lib_xfer+0xf55/0x1170 sound/core/pcm_lib.c:2246
snd_pcm_oss_write3+0x182/0x210 sound/core/oss/pcm_oss.c:1221
io_playback_transfer+0x7a/0x2a0 sound/core/oss/io.c:47
snd_pcm_plug_write_transfer+0x1d0/0x360 sound/core/oss/pcm_plugin.c:624
snd_pcm_oss_write2+0xe0/0x250 sound/core/oss/pcm_oss.c:1353
snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1419 [inline]
snd_pcm_oss_write+0x322/0x880 sound/core/oss/pcm_oss.c:2765
vfs_write+0x1b9/0x690 fs/read_write.c:603
ksys_write+0xce/0x180 fs/read_write.c:658
__do_sys_write fs/read_write.c:670 [inline]
__se_sys_write fs/read_write.c:667 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:667
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17935 Comm: syz-executor.3 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.