[PATCH 6.18 23/43] ASoC: fsl_xcvr: fix missing lock in fsl_xcvr_mode_put()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ziyi Guo <n7l8m4@u.northwestern.edu>

[ Upstream commit f514248727606b9087bc38a284ff686e0093abf1 ]

fsl_xcvr_activate_ctl() has
lockdep_assert_held(&card->snd_card->controls_rwsem),
but fsl_xcvr_mode_put() calls it without acquiring this lock.

Other callers of fsl_xcvr_activate_ctl() in fsl_xcvr_startup() and
fsl_xcvr_shutdown() properly acquire the lock with down_read()/up_read().

Add the missing down_read()/up_read() calls around fsl_xcvr_activate_ctl()
in fsl_xcvr_mode_put() to fix the lockdep assertion and prevent potential
race conditions when multiple userspace threads access the control.

Signed-off-by: Ziyi Guo <n7l8m4@u.northwestern.edu>
Link: https://patch.msgid.link/20260202174112.2018402-1-n7l8m4@u.northwestern.edu
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/soc/fsl/fsl_xcvr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/soc/fsl/fsl_xcvr.c b/sound/soc/fsl/fsl_xcvr.c
index 58db4906a01d5..51669e5fe8888 100644
--- a/sound/soc/fsl/fsl_xcvr.c
+++ b/sound/soc/fsl/fsl_xcvr.c
@@ -223,10 +223,13 @@ static int fsl_xcvr_mode_put(struct snd_kcontrol *kcontrol,
 
 	xcvr->mode = snd_soc_enum_item_to_val(e, item[0]);
 
+	down_read(&card->snd_card->controls_rwsem);
 	fsl_xcvr_activate_ctl(dai, fsl_xcvr_arc_mode_kctl.name,
 			      (xcvr->mode == FSL_XCVR_MODE_ARC));
 	fsl_xcvr_activate_ctl(dai, fsl_xcvr_earc_capds_kctl.name,
 			      (xcvr->mode == FSL_XCVR_MODE_EARC));
+	up_read(&card->snd_card->controls_rwsem);
+
 	/* Allow playback for SPDIF only */
 	rtd = snd_soc_get_pcm_runtime(card, card->dai_link);
 	rtd->pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream_count =
-- 
2.51.0