2022-03-24 23:38:33

by Xiaoke Wang

Subject: [PATCH] drm/msm/mdp5: check the return of kzalloc()

From: Xiaoke Wang <[email protected]>

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 <[email protected]>
---
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 *
--

2022-03-25 18:33:51

by Abhinav Kumar

Subject: Re: [PATCH] drm/msm/mdp5: check the return of kzalloc()

On 3/24/2022 1:36 AM, [email protected] wrote:
> From: Xiaoke Wang <[email protected]>
>
> 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 <[email protected]>
Reviewed-by: Abhinav Kumar <[email protected]>
> ---
> 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 *

2022-04-06 17:54:54

by Rob Clark

Subject: Re: [PATCH] drm/msm/mdp5: check the return of kzalloc()

On Thu, Mar 24, 2022 at 1:37 AM <[email protected]> wrote:
>
> From: Xiaoke Wang <[email protected]>
>
> 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 <[email protected]>
> ---
> 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 *
> --