ALSA: hda: realtek: Fix race at concurrent COEF updates
authorTakashi Iwai <tiwai@suse.de>
Mon, 31 Jan 2022 07:57:38 +0000 (08:57 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 8 Feb 2022 17:34:03 +0000 (18:34 +0100)
commit586d71ddee6c4883215149eea20367df55cd5558
tree52534d64b48c0a5392a1cd89627ffda5efe0ac15
parent0e629052f013eeb61494d4df2f1f647c2a9aef47
ALSA: hda: realtek: Fix race at concurrent COEF updates

commit b837a9f5ab3bdfab9233c9f98a6bef717673a3e5 upstream.

The COEF access is done with two steps: setting the index then read or
write the data.  When multiple COEF accesses are performed
concurrently, the index and data might be paired unexpectedly.
In most cases, this isn't a big problem as the COEF setup is done at
the initialization, but some dynamic changes like the mute LED may hit
such a race.

For avoiding the racy COEF accesses, this patch introduces a new
mutex coef_mutex to alc_spec, and wrap the COEF accessing functions
with it.

Reported-by: Alexander Sergeyev <sergeev917@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220111195229.a77wrpjclqwrx4bx@localhost.localdomain
Link: https://lore.kernel.org/r/20220131075738.24323-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/pci/hda/patch_realtek.c