Re: [PATCH] drm/mm: avoid possible null pointer dereference

Eric Engestrom
2016-05-23T10:27:24Z

On Wed, May 18, 2016 at 10:17:19PM +0200, Heinrich Schuchardt wrote:
> Do not dereference node before the check if node is NULL.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ---
> drivers/gpu/drm/drm_mm.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
> index 04de6fd..cb39f45 100644
> --- a/drivers/gpu/drm/drm_mm.c
> +++ b/drivers/gpu/drm/drm_mm.c
> @@ -179,12 +179,14 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
> int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
> {
> struct drm_mm_node *hole;
> - u64 end = node->start + node->size;
> + u64 end;
> u64 hole_start;
> u64 hole_end;
>
> BUG_ON(node == NULL);
>
> + end = node->start + node->size;
> +
> /* Find the relevant hole to add our node to */
> drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
> if (hole_start > node->start || hole_end < end)
> --
> 2.1.4

Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>