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BUG: KCSAN: data-race in snd_ctl_notify / snd_ctl_notify

read-write to 0xffff888105cdc8a0 of 4 bytes by task 14014 on cpu 1:
 snd_ctl_notify+0x87/0x2f0 sound/core/control.c:155
 loopback_trigger+0x876/0x890 sound/drivers/aloop.c:398
 snd_pcm_do_start sound/core/pcm_native.c:1350 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:1207 [inline]
 snd_pcm_action sound/core/pcm_native.c:1290 [inline]
 snd_pcm_start+0x362/0x490 sound/core/pcm_native.c:1391
 __snd_pcm_lib_xfer+0xfa0/0x1170 sound/core/pcm_lib.c:2247
 snd_pcm_oss_write3+0x182/0x210 sound/core/oss/pcm_oss.c:1221
 snd_pcm_oss_write2+0x13a/0x250 sound/core/oss/pcm_oss.c:1361
 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+0x1d0/0x6b0 fs/read_write.c:584
 ksys_write+0xce/0x180 fs/read_write.c:639
 __do_sys_write fs/read_write.c:651 [inline]
 __se_sys_write fs/read_write.c:648 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:648
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read-write to 0xffff888105cdc8a0 of 4 bytes by task 14005 on cpu 0:
 snd_ctl_notify+0x87/0x2f0 sound/core/control.c:155
 loopback_trigger+0x876/0x890 sound/drivers/aloop.c:398
 snd_pcm_do_start sound/core/pcm_native.c:1350 [inline]
 snd_pcm_action_single sound/core/pcm_native.c:1207 [inline]
 snd_pcm_action sound/core/pcm_native.c:1290 [inline]
 snd_pcm_start+0x362/0x490 sound/core/pcm_native.c:1391
 __snd_pcm_lib_xfer+0xfa0/0x1170 sound/core/pcm_lib.c:2247
 snd_pcm_oss_write3+0x182/0x210 sound/core/oss/pcm_oss.c:1221
 snd_pcm_oss_write2+0x13a/0x250 sound/core/oss/pcm_oss.c:1361
 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+0x1d0/0x6b0 fs/read_write.c:584
 ksys_write+0xce/0x180 fs/read_write.c:639
 __do_sys_write fs/read_write.c:651 [inline]
 __se_sys_write fs/read_write.c:648 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:648
 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: 14005 Comm: syz-executor.3 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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