syzbot

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BUG: KCSAN: data-race in snd_pcm_kernel_ioctl / snd_pcm_kernel_ioctl

write to 0xffff88803537b000 of 4 bytes by task 14011 on cpu 1:
 snd_pcm_set_state sound/core/pcm_native.c:572 [inline]
 snd_pcm_post_prepare sound/core/pcm_native.c:1883 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:1214 [inline]
 snd_pcm_action_nonatomic sound/core/pcm_native.c:1328 [inline]
 snd_pcm_prepare sound/core/pcm_native.c:1920 [inline]
 snd_pcm_kernel_ioctl+0xd1d/0xdc0 sound/core/pcm_native.c:3336
 snd_pcm_oss_prepare sound/core/oss/pcm_oss.c:1128 [inline]
 snd_pcm_oss_make_ready+0x132/0x1f0 sound/core/oss/pcm_oss.c:1156
 snd_pcm_oss_sync+0x142/0x6a0 sound/core/oss/pcm_oss.c:1714
 snd_pcm_oss_ioctl+0x61a/0x29d0 sound/core/oss/pcm_oss.c:2600
 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+0x44/0xae

read to 0xffff88803537b000 of 4 bytes by task 14013 on cpu 0:
 snd_pcm_drop sound/core/pcm_native.c:2131 [inline]
 snd_pcm_kernel_ioctl+0x1d5/0xdc0 sound/core/pcm_native.c:3342
 snd_pcm_oss_set_trigger+0x3cc/0x490 sound/core/oss/pcm_oss.c:2112
 snd_pcm_oss_ioctl+0xd0b/0x29d0 sound/core/oss/pcm_oss.c:2690
 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+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14013 Comm: syz-executor.3 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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