[PATCH] soc: meson: fix a missing check on list iterator

[Xiaomeng Tong]

The bug is here:
	*dai_name = dai->driver->name;

For for_each_component_dais(), just like list_for_each_entry,
the list iterator 'runtime' will point to a bogus position
containing HEAD if the list is empty or no element is found.
This case must be checked before any use of the iterator,
otherwise it will lead to a invalid memory access.

To fix the bug, just move the assignment into loop and return
0 when element is found, otherwise return -EINVAL;

Cc: stable at vger.kernel.org
Fixes: 6ae9ca9ce986b ("ASoC: meson: aiu: add i2s and spdif support")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong at gmail.com>
---
 sound/soc/meson/aiu.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/sound/soc/meson/aiu.c b/sound/soc/meson/aiu.c
index d299a70db7e5..b52915c6f53b 100644
--- a/sound/soc/meson/aiu.c
+++ b/sound/soc/meson/aiu.c
@@ -61,14 +61,14 @@ int aiu_of_xlate_dai_name(struct snd_soc_component *component,
 		return -EINVAL;
 
 	for_each_component_dais(component, dai) {
-		if (id == 0)
-			break;
+		if (id == 0) {
+			*dai_name = dai->driver->name;
+			return 0;
+		}
 		id--;
 	}
 
-	*dai_name = dai->driver->name;
-
-	return 0;
+	return -EINVAL;
 }
 
 static int aiu_cpu_of_xlate_dai_name(struct snd_soc_component *component,
-- 
2.17.1