ASoC: Fix use-after-free at card unregistration
authorTakashi Iwai <tiwai@suse.de>
Wed, 24 May 2017 08:19:45 +0000 (10:19 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 14 Jun 2017 13:06:04 +0000 (15:06 +0200)
commiteb8fa317cb0184f5179e29bab8c62a4a4087cd4a
treea7e07acfa3b14ff7504c0da19f8d14ac1e976caf
parent82ecd2f054bd778eeb97c775c915b052e2941c79
ASoC: Fix use-after-free at card unregistration

commit 4efda5f2130da033aeedc5b3205569893b910de2 upstream.

soc_cleanup_card_resources() call snd_card_free() at the last of its
procedure.  This turned out to lead to a use-after-free.
PCM runtimes have been already removed via soc_remove_pcm_runtimes(),
while it's dereferenced later in soc_pcm_free() called via
snd_card_free().

The fix is simple: just move the snd_card_free() call to the beginning
of the whole procedure.  This also gives another benefit: it
guarantees that all operations have been shut down before actually
releasing the resources, which was racy until now.

Reported-and-tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/soc/soc-core.c