KCSAN: data-race in __snd_pcm_lib_xfer / snd_pcm_oss_sync (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3cea11cd Linux 5.10-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11aa8062500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=82dcf12dec8599cdd9f2
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [alsa-...@alsa-project.org ar...@arndb.de baoli...@linaro.org linux-...@vger.kernel.org paul...@chromium.org pe...@perex.cz ti...@suse.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+82dcf1...@syzkaller.appspotmail.com

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

write to 0xffff88810271f000 of 8 bytes by task 12605 on cpu 1:
pcm_lib_apply_appl_ptr sound/core/pcm_lib.c:2101 [inline]
__snd_pcm_lib_xfer+0xe18/0x1170 sound/core/pcm_lib.c:2236
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

read to 0xffff88810271f000 of 8 bytes by task 12614 on cpu 0:
snd_pcm_oss_sync+0x5be/0x690 sound/core/oss/pcm_oss.c:1678
snd_pcm_oss_ioctl+0x612/0x2900 sound/core/oss/pcm_oss.c:2590
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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12614 Comm: syz-executor.5 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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