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From:   Yassine Oudjana <yassine.oudjana@gmail.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Banajit Goswami <bgoswami@codeaurora.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Cc:     Yassine Oudjana <y.oudjana@protonmail.com>,
        Yassine Oudjana <yassine.oudjana@gmail.com>,
        alsa-devel@alsa-project.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] ASoC: wcd9335: Remove RX channel from old list before adding it to a new one
Date:   Mon,  6 Jun 2022 19:22:26 +0400
Message-Id: <20220606152226.149164-1-y.oudjana@protonmail.com>
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From: Yassine Oudjana <y.oudjana@protonmail.com>

Currently in slim_rx_mux_put, an RX channel gets added to a new list
even if it is already in one. This can mess up links and make either
it, the new list head, or both, get linked to the wrong entries.
This can cause an entry to link to itself which in turn ends up
making list_for_each_entry in other functions loop infinitely.
To avoid issues, always remove the RX channel from any list it's in
before adding it to a new list.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
---
 sound/soc/codecs/wcd9335.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/wcd9335.c b/sound/soc/codecs/wcd9335.c
index 617a36a89dfe..597420679505 100644
--- a/sound/soc/codecs/wcd9335.c
+++ b/sound/soc/codecs/wcd9335.c
@@ -1289,9 +1289,12 @@ static int slim_rx_mux_put(struct snd_kcontrol *kc,
 
 	wcd->rx_port_value[port_id] = ucontrol->value.enumerated.item[0];
 
+	/* Remove channel from any list it's in before adding it to a new one */
+	list_del_init(&wcd->rx_chs[port_id].list);
+
 	switch (wcd->rx_port_value[port_id]) {
 	case 0:
-		list_del_init(&wcd->rx_chs[port_id].list);
+		/* Channel already removed from lists. Nothing to do here */
 		break;
 	case 1:
 		list_add_tail(&wcd->rx_chs[port_id].list,
-- 
2.36.1