[PATCH AUTOSEL 6.2 01/30] drm/cirrus: NULL-check pipe->plane.state->fb in cirrus_pipe_update()

Sasha Levin
2023-03-20T00:53:14Z

From: Alexandr Sapozhnikov <alsp705@gmail.com>

[ Upstream commit 7245e629dcaaf308f1868aeffa218e9849c77893 ]

After having been compared to NULL value at cirrus.c:455, pointer
'pipe->plane.state->fb' is passed as 1st parameter in call to function
'cirrus_fb_blit_rect' at cirrus.c:461, where it is dereferenced at
cirrus.c:316.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

v2:
* aligned commit message to line-length limits

Signed-off-by: Alexandr Sapozhnikov <alsp705@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230215171549.16305-1-alsp705@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/tiny/cirrus.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tiny/cirrus.c b/drivers/gpu/drm/tiny/cirrus.c
index 678c2ef1cae70..ffa7e61dd1835 100644
--- a/drivers/gpu/drm/tiny/cirrus.c
+++ b/drivers/gpu/drm/tiny/cirrus.c
@@ -455,7 +455,7 @@ static void cirrus_pipe_update(struct drm_simple_display_pipe *pipe,
if (state->fb && cirrus->cpp != cirrus_cpp(state->fb))
cirrus_mode_set(cirrus, &crtc->mode, state->fb);

- if (drm_atomic_helper_damage_merged(old_state, state, &rect))
+ if (state->fb && drm_atomic_helper_damage_merged(old_state, state, &rect))
cirrus_fb_blit_rect(state->fb, &shadow_plane_state->data[0], &rect);
}

--
2.39.2