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

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 *