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

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

[Guangshuo Li]

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

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

Keep the cleanup in idxd_conf_engine_release() after put_device() and
avoid freeing engine again in idxd_setup_engines().

Fixes: 817bced19d1d ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_engines")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/dma/idxd/init.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index d9a9d56dd277..4eff74182225 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -310,7 +310,7 @@ static int idxd_setup_engines(struct idxd_device *idxd)
 		rc = dev_set_name(conf_dev, "engine%d.%d", idxd->id, engine->id);
 		if (rc < 0) {
 			put_device(conf_dev);
-			kfree(engine);
+
 			goto err;
 		}
 
@@ -324,7 +324,7 @@ static int idxd_setup_engines(struct idxd_device *idxd)
 		engine = idxd->engines[i];
 		conf_dev = engine_confdev(engine);
 		put_device(conf_dev);
-		kfree(engine);
+
 	}
 	kfree(idxd->engines);
 
@@ -374,7 +374,6 @@ 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);
-
 			goto err;
 		}
 
@@ -399,7 +398,6 @@ static int idxd_setup_groups(struct idxd_device *idxd)
 	while (--i >= 0) {
 		group = idxd->groups[i];
 		put_device(group_confdev(group));
-
 	}
 	kfree(idxd->groups);
 
-- 
2.43.0

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

[Shuai Xue]

On 4/1/26 11:40 AM, Guangshuo Li wrote:
> When an error happens after device_initialize(), idxd_setup_engines()
> calls put_device(conf_dev).
> 
> The device release callback idxd_conf_engine_release() frees engine,
> but the current error paths then call kfree(engine) again, causing a
> double free.
> 
> Keep the cleanup in idxd_conf_engine_release() after put_device() and
> avoid freeing engine again in idxd_setup_engines().
> 
> Fixes: 817bced19d1d ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_engines")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>   drivers/dma/idxd/init.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index d9a9d56dd277..4eff74182225 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -310,7 +310,7 @@ static int idxd_setup_engines(struct idxd_device *idxd)
>   		rc = dev_set_name(conf_dev, "engine%d.%d", idxd->id, engine->id);
>   		if (rc < 0) {
>   			put_device(conf_dev);
> -			kfree(engine);
> +
>   			goto err;
>   		}
>   
> @@ -324,7 +324,7 @@ static int idxd_setup_engines(struct idxd_device *idxd)
>   		engine = idxd->engines[i];
>   		conf_dev = engine_confdev(engine);
>   		put_device(conf_dev);
> -		kfree(engine);
> +
>   	}
>   	kfree(idxd->engines);
>   
> @@ -374,7 +374,6 @@ 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);
> -
>   			goto err;
>   		}
>   
> @@ -399,7 +398,6 @@ static int idxd_setup_groups(struct idxd_device *idxd)
>   	while (--i >= 0) {
>   		group = idxd->groups[i];
>   		put_device(group_confdev(group));
> -
>   	}
>   	kfree(idxd->groups);
>   


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

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

Thanks.
Shuai