KCSAN: data-race in snd_pcm_oss_change_params_locked / snd_pcm_oss_poll

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f01c30de Merge tag 'vfs-5.10-fixes-2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=150365e6500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=3832818348b59ecc2834
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [ak...@linux-foundation.org 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+383281...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in snd_pcm_oss_change_params_locked / snd_pcm_oss_poll

read to 0xffff88801168f700 of 1 bytes by task 18094 on cpu 1:
snd_pcm_oss_change_params_locked+0x1c9f/0x2600 sound/core/oss/pcm_oss.c:981
snd_pcm_oss_make_ready_locked sound/core/oss/pcm_oss.c:1166 [inline]
snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1494 [inline]
snd_pcm_oss_read+0x1a8/0x8a0 sound/core/oss/pcm_oss.c:2742
do_loop_readv_writev fs/read_write.c:761 [inline]
do_iter_read+0x2be/0x4b0 fs/read_write.c:803
vfs_readv fs/read_write.c:921 [inline]
do_readv+0x13d/0x280 fs/read_write.c:958
__do_sys_readv fs/read_write.c:1049 [inline]
__se_sys_readv fs/read_write.c:1046 [inline]
__x64_sys_readv+0x41/0x50 fs/read_write.c:1046
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88801168f700 of 1 bytes by task 18083 on cpu 0:
snd_pcm_oss_poll+0x417/0x510 sound/core/oss/pcm_oss.c:2830
vfs_poll include/linux/poll.h:90 [inline]
do_pollfd fs/select.c:869 [inline]
do_poll fs/select.c:917 [inline]
do_sys_poll+0x611/0xb80 fs/select.c:1011
__do_sys_ppoll fs/select.c:1111 [inline]
__se_sys_ppoll+0x169/0x1b0 fs/select.c:1091
__x64_sys_ppoll+0x63/0x70 fs/select.c:1091
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: 18083 Comm: syz-executor.0 Not tainted 5.10.0-rc3-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.