[PATCH] dmaengine: idxd: fix double free in idxd_setup_groups() error path

[PATCH] dmaengine: idxd: fix double free in idxd_setup_groups() error path

[Guangshuo Li]

When an error happens after device_initialize(), idxd_setup_groups()
calls put_device(conf_dev).

The device release callback idxd_conf_group_release() frees group, but
the current error paths then call kfree(group) again, causing a double
free.

Keep the cleanup in idxd_conf_group_release() after put_device() and
avoid freeing group again in idxd_setup_groups().

Fixes: aa6f4f945b10 ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_groups")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/dma/idxd/init.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index b782eb3c191d..d9a9d56dd277 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -374,7 +374,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
 		rc = dev_set_name(conf_dev, "group%d.%d", idxd->id, group->id);
 		if (rc < 0) {
 			put_device(conf_dev);
-			kfree(group);
+
 			goto err;
 		}
 
@@ -399,7 +399,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
 	while (--i >= 0) {
 		group = idxd->groups[i];
 		put_device(group_confdev(group));
-		kfree(group);
+
 	}
 	kfree(idxd->groups);
 
-- 
2.43.0

Re: [PATCH] dmaengine: idxd: fix double free in idxd_setup_groups() error path

[Shuai Xue]

On 4/1/26 11:36 AM, Guangshuo Li wrote:
> When an error happens after device_initialize(), idxd_setup_groups()
> calls put_device(conf_dev).
> 
> The device release callback idxd_conf_group_release() frees group, but
> the current error paths then call kfree(group) again, causing a double
> free.
> 
> Keep the cleanup in idxd_conf_group_release() after put_device() and
> avoid freeing group again in idxd_setup_groups().

Yes, I think it is a double free.
Sorry, I missed the idxd_conf_group_release path.

> 
> Fixes: aa6f4f945b10 ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_groups")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>   drivers/dma/idxd/init.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index b782eb3c191d..d9a9d56dd277 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -374,7 +374,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   		rc = dev_set_name(conf_dev, "group%d.%d", idxd->id, group->id);
>   		if (rc < 0) {
>   			put_device(conf_dev);
> -			kfree(group);
> +
>   			goto err;
>   		}
>   
> @@ -399,7 +399,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   	while (--i >= 0) {
>   		group = idxd->groups[i];
>   		put_device(group_confdev(group));
> -		kfree(group);
> +

Nit: please remove the blank lines left behind by both deletions.

With those addressed:

Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>

Thanks.
Shuai

Re: [PATCH] dmaengine: idxd: fix double free in idxd_setup_groups() error path

[Shuai Xue]

On 4/1/26 11:36 AM, Guangshuo Li wrote:
> When an error happens after device_initialize(), idxd_setup_groups()
> calls put_device(conf_dev).
> 
> The device release callback idxd_conf_group_release() frees group, but
> the current error paths then call kfree(group) again, causing a double
> free.
> 
> Keep the cleanup in idxd_conf_group_release() after put_device() and
> avoid freeing group again in idxd_setup_groups().
> 
> Fixes: aa6f4f945b10 ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_groups")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>   drivers/dma/idxd/init.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index b782eb3c191d..d9a9d56dd277 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -374,7 +374,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   		rc = dev_set_name(conf_dev, "group%d.%d", idxd->id, group->id);
>   		if (rc < 0) {
>   			put_device(conf_dev);
> -			kfree(group);
> +
>   			goto err;
>   		}
>   
> @@ -399,7 +399,7 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   	while (--i >= 0) {
>   		group = idxd->groups[i];
>   		put_device(group_confdev(group));
> -		kfree(group);
> +
>   	}
>   	kfree(idxd->groups);
>   

Note that idxd_clean_groups() and idxd_clean_engines() have the same pattern.
It should be fixed in the same patch as well.

Thanks.
Shuai