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BUG: KCSAN: data-race in snd_ctl_notify / snd_ctl_notify

read to 0xffff8881268de858 of 4 bytes by interrupt on cpu 0:
 snd_ctl_notify sound/core/control.c:154 [inline]
 snd_ctl_notify+0xd7/0x3b0 sound/core/control.c:141
 loopback_active_notify+0xcb/0xe0 sound/drivers/aloop.c:242
 loopback_trigger+0x59f/0x710 sound/drivers/aloop.c:296
 snd_pcm_do_stop sound/core/pcm_native.c:1279 [inline]
 snd_pcm_do_stop+0xe6/0xf0 sound/core/pcm_native.c:1275
 snd_pcm_action_single+0x5a/0xc0 sound/core/pcm_native.c:1072
 snd_pcm_action+0x83/0x90 sound/core/pcm_native.c:1155
 snd_pcm_stop+0x2e/0x40 sound/core/pcm_native.c:1312
 __snd_pcm_xrun+0x92/0x300 sound/core/pcm_lib.c:149
 snd_pcm_update_state+0x31f/0x330 sound/core/pcm_lib.c:190
 snd_pcm_update_hw_ptr0+0xa05/0x1280 sound/core/pcm_lib.c:453
 snd_pcm_period_elapsed+0x141/0x1c0 sound/core/pcm_lib.c:1791
 loopback_timer_function+0x130/0x137 sound/drivers/aloop.c:525
 call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0xcb8/0xd20 kernel/time/timer.c:1786

write to 0xffff8881268de858 of 4 bytes by interrupt on cpu 1:
 snd_ctl_notify sound/core/control.c:154 [inline]
 snd_ctl_notify+0xe9/0x3b0 sound/core/control.c:141
 loopback_active_notify+0xcb/0xe0 sound/drivers/aloop.c:242
 loopback_trigger+0x59f/0x710 sound/drivers/aloop.c:296
 snd_pcm_do_stop sound/core/pcm_native.c:1279 [inline]
 snd_pcm_do_stop+0xe6/0xf0 sound/core/pcm_native.c:1275
 snd_pcm_action_single+0x5a/0xc0 sound/core/pcm_native.c:1072
 snd_pcm_action+0x83/0x90 sound/core/pcm_native.c:1155
 snd_pcm_stop+0x2e/0x40 sound/core/pcm_native.c:1312
 __snd_pcm_xrun+0x92/0x300 sound/core/pcm_lib.c:149
 snd_pcm_update_state+0x31f/0x330 sound/core/pcm_lib.c:190
 snd_pcm_update_hw_ptr0+0xa05/0x1280 sound/core/pcm_lib.c:453
 snd_pcm_period_elapsed+0x141/0x1c0 sound/core/pcm_lib.c:1791
 loopback_timer_function+0x130/0x137 sound/drivers/aloop.c:525
 call_timer_fn+0x5f/0x2f0 kernel/time/timer.c:1404

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1956 Comm: syz-executor.2 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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