mm/page_owner: fix memory leak in page_owner_stack_fops->release()

[PATCH] mm/page_owner: fix memory leak in page_owner_stack_fops->release()

Posted by ranxiaokai627@163.com 1 month, 2 weeks ago

From: Ran Xiaokai <ran.xiaokai@zte.com.cn>

The page_owner_stack_fops->open() callback invokes seq_open_private(),
therefore its corresponding ->release() callback must call seq_release_private().
Otherwise it will cause a memory leak of struct stack_print_ctx.

Fixes: 765973a098037 ("mm,page_owner: display all stacks and their count")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
---
 mm/page_owner.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 27d19f01009c..b6a394a130ec 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -952,7 +952,7 @@ static const struct file_operations page_owner_stack_fops = {
 	.open		= page_owner_stack_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= seq_release,
+	.release	= seq_release_private,
 };
 
 static int page_owner_threshold_get(void *data, u64 *val)
-- 
2.25.1

Re: [PATCH] mm/page_owner: fix memory leak in page_owner_stack_fops->release()

Posted by Vlastimil Babka 1 month, 2 weeks ago

On 12/19/25 08:42, ranxiaokai627@163.com wrote:
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> 
> The page_owner_stack_fops->open() callback invokes seq_open_private(),
> therefore its corresponding ->release() callback must call seq_release_private().
> Otherwise it will cause a memory leak of struct stack_print_ctx.
> 
> Fixes: 765973a098037 ("mm,page_owner: display all stacks and their count")

I think cc: stable is warranted, Andrew can add it if he agrees.

> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

Thanks!

> ---
>  mm/page_owner.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 27d19f01009c..b6a394a130ec 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -952,7 +952,7 @@ static const struct file_operations page_owner_stack_fops = {
>  	.open		= page_owner_stack_open,
>  	.read		= seq_read,
>  	.llseek		= seq_lseek,
> -	.release	= seq_release,
> +	.release	= seq_release_private,
>  };
>  
>  static int page_owner_threshold_get(void *data, u64 *val)

Re: [PATCH] mm/page_owner: fix memory leak in page_owner_stack_fops->release()

Posted by Michal Hocko 1 month, 2 weeks ago

On Fri 19-12-25 07:42:32, ranxiaokai627@163.com wrote:
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> 
> The page_owner_stack_fops->open() callback invokes seq_open_private(),
> therefore its corresponding ->release() callback must call seq_release_private().
> Otherwise it will cause a memory leak of struct stack_print_ctx.
> 
> Fixes: 765973a098037 ("mm,page_owner: display all stacks and their count")
> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>

Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!

> ---
>  mm/page_owner.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 27d19f01009c..b6a394a130ec 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -952,7 +952,7 @@ static const struct file_operations page_owner_stack_fops = {
>  	.open		= page_owner_stack_open,
>  	.read		= seq_read,
>  	.llseek		= seq_lseek,
> -	.release	= seq_release,
> +	.release	= seq_release_private,
>  };
>  
>  static int page_owner_threshold_get(void *data, u64 *val)
> -- 
> 2.25.1

-- 
Michal Hocko
SUSE Labs