[PATCH v4] ASoC: samsung: i2s: Null pointer dereference on samsung_i2s_remove

[PATCH v4] ASoC: samsung: i2s: Null pointer dereference on samsung_i2s_remove

[Anton Vasilyev]

If (quirks & QUIRK_SEC_DAI == 0) then samsung_i2s_probe() doesn't allocate
sec_dai and pri_dai->sec_dai remains Null, but samsung_i2s_remove()
performs pri_dai->sec_dai dereference in any case.

The patch removes useless reinitialization of sec_dai at
samsung_i2s_remove(), because resources are under devm control.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
---
v2: Drop initialization of sec_dai by NULL at samsung_i2s_remove
as Sylwester Nawrocki suggest.
---
v3: Fix typo in the comment
---
v4: Change comment based on Krzysztof review.
---
 sound/soc/samsung/i2s.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6f896e3 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1376,13 +1376,9 @@ static int samsung_i2s_probe(struct platform_device *pdev)
 
 static int samsung_i2s_remove(struct platform_device *pdev)
 {
-	struct i2s_dai *pri_dai, *sec_dai;
+	struct i2s_dai *pri_dai;
 
 	pri_dai = dev_get_drvdata(&pdev->dev);
-	sec_dai = pri_dai->sec_dai;
-
-	pri_dai->sec_dai = NULL;
-	sec_dai->pri_dai = NULL;
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-- 
2.7.4

Re: [PATCH v4] ASoC: samsung: i2s: Null pointer dereference on samsung_i2s_remove

[Krzysztof Kozlowski]

On Tue, Aug 15, 2017 at 03:19:54PM +0300, Anton Vasilyev wrote:
> If (quirks & QUIRK_SEC_DAI == 0) then samsung_i2s_probe() doesn't allocate
> sec_dai and pri_dai->sec_dai remains Null, but samsung_i2s_remove()
> performs pri_dai->sec_dai dereference in any case.
> 
> The patch removes useless reinitialization of sec_dai at
> samsung_i2s_remove(), because resources are under devm control.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
> ---
> v2: Drop initialization of sec_dai by NULL at samsung_i2s_remove
> as Sylwester Nawrocki suggest.
> ---
> v3: Fix typo in the comment
> ---
> v4: Change comment based on Krzysztof review.
> ---
>  sound/soc/samsung/i2s.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 

Acked-by: Krzysztof Kozlowski <krzk@kernel.org>

Best regards,
Krzysztof