[PATCH 5.4 124/320] ALSA: PCM: Add missing rwsem around snd_ctl_remove() calls

Greg Kroah-Hartman
2022-01-24T20:11:28Z

From: Takashi Iwai <tiwai@suse.de>

[ Upstream commit 5471e9762e1af4b7df057a96bfd46cc250979b88 ]

snd_ctl_remove() has to be called with card->controls_rwsem held (when
called after the card instantiation). This patch add the missing
rwsem calls around it.

Fixes: a8ff48cb7083 ("ALSA: pcm: Free chmap at PCM free callback, too")
Link: https://lore.kernel.org/r/20211116071314.15065-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/core/pcm.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 9a72d641743d9..f8ce961c28d6e 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -810,7 +810,11 @@ EXPORT_SYMBOL(snd_pcm_new_internal);
static void free_chmap(struct snd_pcm_str *pstr)
{
if (pstr->chmap_kctl) {
- snd_ctl_remove(pstr->pcm->card, pstr->chmap_kctl);
+ struct snd_card *card = pstr->pcm->card;
+
+ down_write(&card->controls_rwsem);
+ snd_ctl_remove(card, pstr->chmap_kctl);
+ up_write(&card->controls_rwsem);
pstr->chmap_kctl = NULL;
}
}
--
2.34.1