devres: Fix memory leakage due to driver API devm_free_percpu()

[PATCH v1] devres: Fix memory leakage due to driver API devm_free_percpu()

Posted by Zijun Hu 1 year, 6 months ago

It will cause memory leakage when use driver API devm_free_percpu()
to free memory allocated by devm_alloc_percpu(), fixed by using
devres_release() instead of devres_destroy() within devm_free_percpu().

Fixes: ff86aae3b411 ("devres: add devm_alloc_percpu()")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/base/devres.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 3df0025d12aa..082dbb296b6e 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -1222,7 +1222,11 @@ EXPORT_SYMBOL_GPL(__devm_alloc_percpu);
  */
 void devm_free_percpu(struct device *dev, void __percpu *pdata)
 {
-	WARN_ON(devres_destroy(dev, devm_percpu_release, devm_percpu_match,
+	/*
+	 * Use devres_release() to prevent memory leakage as
+	 * devm_free_pages() does.
+	 */
+	WARN_ON(devres_release(dev, devm_percpu_release, devm_percpu_match,
 			       (__force void *)pdata));
 }
 EXPORT_SYMBOL_GPL(devm_free_percpu);
-- 
2.7.4

Re: [PATCH v1] devres: Fix memory leakage due to driver API devm_free_percpu()

Posted by Greg KH 1 year, 6 months ago

On Wed, Jun 19, 2024 at 09:38:01PM +0800, Zijun Hu wrote:
> It will cause memory leakage when use driver API devm_free_percpu()
> to free memory allocated by devm_alloc_percpu(), fixed by using
> devres_release() instead of devres_destroy() within devm_free_percpu().
> 
> Fixes: ff86aae3b411 ("devres: add devm_alloc_percpu()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
> ---
>  drivers/base/devres.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> index 3df0025d12aa..082dbb296b6e 100644
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -1222,7 +1222,11 @@ EXPORT_SYMBOL_GPL(__devm_alloc_percpu);
>   */
>  void devm_free_percpu(struct device *dev, void __percpu *pdata)
>  {
> -	WARN_ON(devres_destroy(dev, devm_percpu_release, devm_percpu_match,
> +	/*
> +	 * Use devres_release() to prevent memory leakage as
> +	 * devm_free_pages() does.
> +	 */
> +	WARN_ON(devres_release(dev, devm_percpu_release, devm_percpu_match,
>  			       (__force void *)pdata));
>  }
>  EXPORT_SYMBOL_GPL(devm_free_percpu);
> -- 
> 2.7.4
> 
> 

These are good fixes, how are you finding them?  Care to write up some
kunit tests for the devres apis?

thanks,

greg k-h

Re: [PATCH v1] devres: Fix memory leakage due to driver API devm_free_percpu()

Posted by quic_zijuhu 1 year, 5 months ago

On 6/19/2024 10:53 PM, Greg KH wrote:
> On Wed, Jun 19, 2024 at 09:38:01PM +0800, Zijun Hu wrote:
>> It will cause memory leakage when use driver API devm_free_percpu()
>> to free memory allocated by devm_alloc_percpu(), fixed by using
>> devres_release() instead of devres_destroy() within devm_free_percpu().
>>
>> Fixes: ff86aae3b411 ("devres: add devm_alloc_percpu()")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
>> ---
>>  drivers/base/devres.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
>> index 3df0025d12aa..082dbb296b6e 100644
>> --- a/drivers/base/devres.c
>> +++ b/drivers/base/devres.c
>> @@ -1222,7 +1222,11 @@ EXPORT_SYMBOL_GPL(__devm_alloc_percpu);
>>   */
>>  void devm_free_percpu(struct device *dev, void __percpu *pdata)
>>  {
>> -	WARN_ON(devres_destroy(dev, devm_percpu_release, devm_percpu_match,
>> +	/*
>> +	 * Use devres_release() to prevent memory leakage as
>> +	 * devm_free_pages() does.
>> +	 */
>> +	WARN_ON(devres_release(dev, devm_percpu_release, devm_percpu_match,
>>  			       (__force void *)pdata));
>>  }
>>  EXPORT_SYMBOL_GPL(devm_free_percpu);
>> -- 
>> 2.7.4
>>
>>
> 
> These are good fixes, how are you finding them?  Care to write up some
> kunit tests for the devres apis?
> 
find them by reading code.😀
> thanks,
> 
> greg k-h