This is a note to let you know that I've just added the patch titled drm/ast: potential dereference of null pointer to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-ast-potential-dereference-of-null-pointer.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c54e0e5065d7c4bd0f697ae3c10ec1741496fc64 Author: Jiasheng Jiang <jiasheng@xxxxxxxxxxx> Date: Tue Dec 14 09:41:26 2021 +0800 drm/ast: potential dereference of null pointer [ Upstream commit fea3fdf975dd9f3e5248afaab8fe023db313f005 ] The return value of kzalloc() needs to be checked. To avoid use of null pointer '&ast_state->base' in case of the failure of alloc. Fixes: f0adbc382b8b ("drm/ast: Allocate initial CRTC state of the correct size") Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/20211214014126.2211535-1-jiasheng@xxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index a3c2f76668abe..d27f2840b9555 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -857,7 +857,10 @@ static void ast_crtc_reset(struct drm_crtc *crtc) if (crtc->state) crtc->funcs->atomic_destroy_state(crtc, crtc->state); - __drm_atomic_helper_crtc_reset(crtc, &ast_state->base); + if (ast_state) + __drm_atomic_helper_crtc_reset(crtc, &ast_state->base); + else + __drm_atomic_helper_crtc_reset(crtc, NULL); } static struct drm_crtc_state *