diff mbox series

drm/msm/mdp5: check the return of kzalloc()

Message ID tencent_F71D40EE9851737338A6289EC3A3942EFE09@qq.com (mailing list archive)
State New, archived
Headers show
Series drm/msm/mdp5: check the return of kzalloc() | expand

Commit Message

Xiaoke Wang March 24, 2022, 8:36 a.m. UTC 
From: Xiaoke Wang <xkernel.wang@foxmail.com>

kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it to
prevent potential wrong memory access.

Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
---
 drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--

Comments

Abhinav Kumar March 24, 2022, 5:58 p.m. UTC | #1 
On 3/24/2022 1:36 AM, xkernel.wang@foxmail.com wrote:
> From: Xiaoke Wang <xkernel.wang@foxmail.com>
> 
> kzalloc() is a memory allocation function which can return NULL when
> some internal memory errors happen. So it is better to check it to
> prevent potential wrong memory access.
> 
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> index c6b69af..5f914cc 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> @@ -90,15 +90,18 @@ static void mdp5_plane_reset(struct drm_plane *plane)
>   		__drm_atomic_helper_plane_destroy_state(plane->state);
>   
>   	kfree(to_mdp5_plane_state(plane->state));
> -	mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
> +	plane->state = NULL;
>   
> -	if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> -		mdp5_state->base.zpos = STAGE_BASE;
> -	else
> -		mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
> -	mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
> +	mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
> +	if (mdp5_state) {
> +		if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> +			mdp5_state->base.zpos = STAGE_BASE;
> +		else
> +			mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
> +		mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
>   
> -	__drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
> +		__drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
> +	}
>   }
>   
>   static struct drm_plane_state *
Rob Clark April 6, 2022, 4:24 p.m. UTC | #2 
On Thu, Mar 24, 2022 at 1:37 AM <xkernel.wang@foxmail.com> wrote:
>
> From: Xiaoke Wang <xkernel.wang@foxmail.com>
>
> kzalloc() is a memory allocation function which can return NULL when
> some internal memory errors happen. So it is better to check it to
> prevent potential wrong memory access.
>
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
> ---
>  drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> index c6b69af..5f914cc 100644
> --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
> @@ -90,15 +90,18 @@ static void mdp5_plane_reset(struct drm_plane *plane)
>                 __drm_atomic_helper_plane_destroy_state(plane->state);
>
>         kfree(to_mdp5_plane_state(plane->state));
> -       mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
> +       plane->state = NULL;

At this point, you could just:

    if (!mdp5_state)
       return;

BR,
-R

>
> -       if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> -               mdp5_state->base.zpos = STAGE_BASE;
> -       else
> -               mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
> -       mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
> +       mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
> +       if (mdp5_state) {
> +               if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> +                       mdp5_state->base.zpos = STAGE_BASE;
> +               else
> +                       mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
> +               mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
>
> -       __drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
> +               __drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
> +       }
>  }
>
>  static struct drm_plane_state *
> --
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
index c6b69af..5f914cc 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c
@@ -90,15 +90,18 @@  static void mdp5_plane_reset(struct drm_plane *plane)
 		__drm_atomic_helper_plane_destroy_state(plane->state);
 
 	kfree(to_mdp5_plane_state(plane->state));
-	mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
+	plane->state = NULL;
 
-	if (plane->type == DRM_PLANE_TYPE_PRIMARY)
-		mdp5_state->base.zpos = STAGE_BASE;
-	else
-		mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
-	mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
+	mdp5_state = kzalloc(sizeof(*mdp5_state), GFP_KERNEL);
+	if (mdp5_state) {
+		if (plane->type == DRM_PLANE_TYPE_PRIMARY)
+			mdp5_state->base.zpos = STAGE_BASE;
+		else
+			mdp5_state->base.zpos = STAGE0 + drm_plane_index(plane);
+		mdp5_state->base.normalized_zpos = mdp5_state->base.zpos;
 
-	__drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
+		__drm_atomic_helper_plane_reset(plane, &mdp5_state->base);
+	}
 }
 
 static struct drm_plane_state *