[PATCH 5.17 124/146] codecs: rt5682s: fix an incorrect NULL check on list iterator

From: Greg Kroah-Hartman
Date: Tue Apr 26 2022 - 05:37:56 EST

From: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>

commit acc72863e0f11cd0bedc888b663700229f9ba5ff upstream.

The bug is here:
if (!dai) {

The list iterator value 'dai' will *always* be set and non-NULL
by for_each_component_dais(), so it is incorrect to assume that
the iterator value will be NULL if the list is empty or no element
is found (In fact, it will be a bogus pointer to an invalid struct
object containing the HEAD). Otherwise it will bypass the check
'if (!dai) {' (never call dev_err() and never return -ENODEV;)
and lead to invalid memory access lately when calling
'rt5682s_set_bclk1_ratio(dai, factor);'.

To fix the bug, just return rt5682s_set_bclk1_ratio(dai, factor);
when found the 'dai', otherwise dev_err() and return -ENODEV;

Cc: stable@xxxxxxxxxxxxxxx
Fixes: bdd229ab26be9 ("ASoC: rt5682s: Add driver for ALC5682I-VS codec")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220327081300.12962-1-xiam0nd.tong@xxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
sound/soc/codecs/rt5682s.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

--- a/sound/soc/codecs/rt5682s.c
+++ b/sound/soc/codecs/rt5682s.c
@@ -2679,14 +2679,11 @@ static int rt5682s_bclk_set_rate(struct

for_each_component_dais(component, dai)
if (dai->id == RT5682S_AIF1)
- break;
- if (!dai) {
- dev_err(component->dev, "dai %d not found in component\n",
- RT5682S_AIF1);
- return -ENODEV;
- }
+ return rt5682s_set_bclk1_ratio(dai, factor);

- return rt5682s_set_bclk1_ratio(dai, factor);
+ dev_err(component->dev, "dai %d not found in component\n",
+ RT5682S_AIF1);
+ return -ENODEV;

static const struct clk_ops rt5682s_dai_clk_ops[RT5682S_DAI_NUM_CLKS] = {