From: Takashi Iwai <ti...@suse.de>
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.jarz...@free.fr>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Takashi Iwai <ti...@suse.de>
---
sound/soc/soc-core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 2722bb0c5573..98d60f471c5d 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2286,6 +2286,9 @@ static int soc_cleanup_card_resources(struct snd_soc_card
*card)
list_for_each_entry(rtd, &card->rtd_list, list)
flush_delayed_work(&rtd->delayed_work);
+ /* free the ALSA card at first; this syncs with pending operations */
+ snd_card_free(card->snd_card);
+
/* remove and free each DAI */
soc_remove_dai_links(card);
soc_remove_pcm_runtimes(card);
@@ -2300,9 +2303,7 @@ static int soc_cleanup_card_resources(struct snd_soc_card
*card)
if (card->remove)
card->remove(card);
- snd_card_free(card->snd_card);
return 0;
-
}
/* removes a socdev */
--
2.1.4
