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

[Sylwester Nawrocki]

On 08/10/2017 05:56 PM, 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()
permorms pri_dai->sec_dai dereference in any case.


s/permorms/performs


The patch adds sec_dai check on Null before derefence at
samsung_i2s_remove().

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

Signed-off-by: Anton Vasilyev 
---
  sound/soc/samsung/i2s.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6beeea8 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1382,7 +1382,8 @@ static int samsung_i2s_remove(struct platform_device 
*pdev)
sec_dai = pri_dai->sec_dai;
  
  	pri_dai->sec_dai = NULL;

-   sec_dai->pri_dai = NULL;


Thanks for the patch.  AFAICS above 4 lines could be removed altogether
since pri_dai and sec_dai is being allocated with devm_kzalloc().
So initializing in remove() is meaningless as afterwards the data will
not be used any more.  The memory will be just freed by the devres code.


+   if (sec_dai)
+   sec_dai->pri_dai = NULL;


--
Regards,
Sylwester

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

[Sylwester Nawrocki]

On 08/10/2017 05:56 PM, 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()
permorms pri_dai->sec_dai dereference in any case.


s/permorms/performs


The patch adds sec_dai check on Null before derefence at
samsung_i2s_remove().

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

Signed-off-by: Anton Vasilyev 
---
  sound/soc/samsung/i2s.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6beeea8 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1382,7 +1382,8 @@ static int samsung_i2s_remove(struct platform_device 
*pdev)
sec_dai = pri_dai->sec_dai;
  
  	pri_dai->sec_dai = NULL;

-   sec_dai->pri_dai = NULL;


Thanks for the patch.  AFAICS above 4 lines could be removed altogether
since pri_dai and sec_dai is being allocated with devm_kzalloc().
So initializing in remove() is meaningless as afterwards the data will
not be used any more.  The memory will be just freed by the devres code.


+   if (sec_dai)
+   sec_dai->pri_dai = NULL;


--
Regards,
Sylwester

[PATCH] 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()
permorms pri_dai->sec_dai dereference in any case.

The patch adds sec_dai check on Null before derefence at
samsung_i2s_remove().

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

Signed-off-by: Anton Vasilyev 
---
 sound/soc/samsung/i2s.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6beeea8 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1382,7 +1382,8 @@ static int samsung_i2s_remove(struct platform_device 
*pdev)
sec_dai = pri_dai->sec_dai;
 
pri_dai->sec_dai = NULL;
-   sec_dai->pri_dai = NULL;
+   if (sec_dai)
+   sec_dai->pri_dai = NULL;
 
pm_runtime_get_sync(>dev);
pm_runtime_disable(>dev);
-- 
2.7.4

[PATCH] 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()
permorms pri_dai->sec_dai dereference in any case.

The patch adds sec_dai check on Null before derefence at
samsung_i2s_remove().

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

Signed-off-by: Anton Vasilyev 
---
 sound/soc/samsung/i2s.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index af3ba4d..6beeea8 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1382,7 +1382,8 @@ static int samsung_i2s_remove(struct platform_device 
*pdev)
sec_dai = pri_dai->sec_dai;
 
pri_dai->sec_dai = NULL;
-   sec_dai->pri_dai = NULL;
+   if (sec_dai)
+   sec_dai->pri_dai = NULL;
 
pm_runtime_get_sync(>dev);
pm_runtime_disable(>dev);
-- 
2.7.4