From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 16 Nov 2021 07:13:13 +0000 (+0100)
Subject: ALSA: PCM: Add missing rwsem around snd_ctl_remove() calls
X-Git-Tag: v4.4.300~70
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=beda1b1318042fd4c9ad80b9c6f04ddfe15960ff;p=thirdparty%2Fkernel%2Fstable.git

ALSA: PCM: Add missing rwsem around snd_ctl_remove() calls

[ 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>
---

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index cdff5f9764808..6ae28dcd79945 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -857,7 +857,11 @@ 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;
 	}
 }