drm/sti: avoid potential dereference of error pointers

commit 831214f77037de02afc287eae93ce97f218d8c04 upstream.

The return value of drm_atomic_get_crtc_state() needs to be
checked. To avoid use of error pointer 'crtc_state' in case
of the failure.

Cc: stable@vger.kernel.org
Fixes: dd86dc2f9ae1 ("drm/sti: implement atomic_check for the planes")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20240913090412.2022848-1-make24@iscas.ac.cn
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/sti/sti_cursor.c b/drivers/gpu/drm/sti/sti_cursor.c
index 1d6051b4f6fedd0c6e51e741d433b10d3f1af3f2..9884991a6e66f5ce138e87387028bb88aaa3e68e 100644 (file)
--- a/drivers/gpu/drm/sti/sti_cursor.c
+++ b/drivers/gpu/drm/sti/sti_cursor.c
@@ -199,6 +199,9 @@ static int sti_cursor_atomic_check(struct drm_plane *drm_plane,
                return 0;
 
        crtc_state = drm_atomic_get_crtc_state(state, crtc);
+       if (IS_ERR(crtc_state))
+               return PTR_ERR(crtc_state);
+
        mode = &crtc_state->mode;
        dst_x = new_plane_state->crtc_x;
        dst_y = new_plane_state->crtc_y;