[lvc-project] [PATCH 5.10/5.15] drm/sun4i: backend: fix error pointer dereference

[Elizaveta Tereshkina]

From: Ethan Tidmore <ethantidmore06 at gmail.com>

commit 06277983eca4a31d3c2114fa33d99a6e82484b11 upstream.

The function drm_atomic_get_plane_state() can return an error pointer
and is not checked for it. Add error pointer check.

Detected by Smatch:
drivers/gpu/drm/sun4i/sun4i_backend.c:496 sun4i_backend_atomic_check() error:
'plane_state' dereferencing possible ERR_PTR()

Fixes: 96180dde23b79 ("drm/sun4i: backend: Add a custom atomic_check for the frontend")
Signed-off-by: Ethan Tidmore <ethantidmore06 at gmail.com>
Reviewed-by: Chen-Yu Tsai <wens at kernel.org>
Link: https://patch.msgid.link/20260217014801.60760-1-ethantidmore06@gmail.com
Signed-off-by: Chen-Yu Tsai <wens at kernel.org>
Signed-off-by: Elizaveta Tereshkina <etereshkina at astralinux.ru>
---
Backport fix for CVE-2026-53066
 drivers/gpu/drm/sun4i/sun4i_backend.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index d935f36a24dd..b3741827c6c3 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -507,6 +507,9 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
 		struct drm_plane_state *plane_state =
 			drm_atomic_get_plane_state(state, plane);
+		if (IS_ERR(plane_state))
+			return PTR_ERR(plane_state);
+
 		struct sun4i_layer_state *layer_state =
 			state_to_sun4i_layer_state(plane_state);
 		struct drm_framebuffer *fb = plane_state->fb;
-- 
2.39.2