[PATCH v2] ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put()

[PATCH v2] ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put()

[Ziyi Guo]

This reverts commit f51424872760 ("ASoC: fsl_xcvr: fix missing lock in fsl_xcvr_mode_put()").

The original patch attempted to acquire the card->controls_rwsem lock in
fsl_xcvr_mode_put(). However, this function is called from the upper ALSA
core function snd_ctl_elem_write(), which already holds the write lock on
controls_rwsem for the whole put operation. So there is no need to simply
hold the lock for fsl_xcvr_activate_ctl() again.

Acquiring the read lock while holding the write lock in the same thread
results in a deadlock and a hung task, as reported by Alexander Stein.

Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Closes: https://lore.kernel.org/linux-sound/5056506.GXAFRqVoOG@steina-w/
Signed-off-by: Ziyi Guo <n7l8m4@u.northwestern.edu>
---
v2:
 - Refactor subject line style
 - Include human readable descriptions
 - Fix the sha1 information for sound/soc/fsl/fsl_xcvr.c

 sound/soc/fsl/fsl_xcvr.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/sound/soc/fsl/fsl_xcvr.c b/sound/soc/fsl/fsl_xcvr.c
index 5de93f458b56..a268fb81a2f8 100644
--- a/sound/soc/fsl/fsl_xcvr.c
+++ b/sound/soc/fsl/fsl_xcvr.c
@@ -223,13 +223,10 @@ 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 =
-- 
2.34.1

Re: [PATCH v2] ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put()

[Mark Brown]

On Tue, 10 Feb 2026 18:57:14 +0000, Ziyi Guo wrote:
> This reverts commit f51424872760 ("ASoC: fsl_xcvr: fix missing lock in fsl_xcvr_mode_put()").
> 
> The original patch attempted to acquire the card->controls_rwsem lock in
> fsl_xcvr_mode_put(). However, this function is called from the upper ALSA
> core function snd_ctl_elem_write(), which already holds the write lock on
> controls_rwsem for the whole put operation. So there is no need to simply
> hold the lock for fsl_xcvr_activate_ctl() again.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: fsl_xcvr: Revert fix missing lock in fsl_xcvr_mode_put()
      commit: 9f16d96e1222391a6b996a1b676bec14fb91e3b2

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark