ASoC: rt5682: fix an incorrect NULL check on list iterator

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
'rt5682_set_bclk1_ratio(dai, factor);'.

To fix the bug, just return rt5682_set_bclk1_ratio(dai, factor);
when found the 'dai', otherwise dev_err() and return -ENODEV;

Cc: stable@vger.kernel.org
Fixes: ebbfabc16d23d ("ASoC: rt5682: Add CCF usage for providing I2S clks")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220327081002.12684-1-xiam0nd.tong@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/rt5682.c b/sound/soc/codecs/rt5682.c
index be68d57..c9ff9c8 100644 (file)
--- a/sound/soc/codecs/rt5682.c
+++ b/sound/soc/codecs/rt5682.c
@@ -2822,14 +2822,11 @@ static int rt5682_bclk_set_rate(struct clk_hw *hw, unsigned long rate,
 
        for_each_component_dais(component, dai)
                if (dai->id == RT5682_AIF1)
-                       break;
-       if (!dai) {
-               dev_err(rt5682->i2c_dev, "dai %d not found in component\n",
-                       RT5682_AIF1);
-               return -ENODEV;
-       }
+                       return rt5682_set_bclk1_ratio(dai, factor);
 
-       return rt5682_set_bclk1_ratio(dai, factor);
+       dev_err(rt5682->i2c_dev, "dai %d not found in component\n",
+               RT5682_AIF1);
+       return -ENODEV;
 }
 
 static const struct clk_ops rt5682_dai_clk_ops[RT5682_DAI_NUM_CLKS] = {