Hello Javier Martinez Canillas,
The patch fdd591e00a9c: "drm/ssd130x: Add support for the SSD132x
OLED controller family" from Oct 14, 2023 (linux-next), leads to the
following Smatch static checker warning:
drivers/gpu/drm/solomon/ssd130x.c:921 ssd132x_primary_plane_atomic_check()
error: uninitialized symbol 'crtc_state'.
drivers/gpu/drm/solomon/ssd130x.c
905 static int ssd132x_primary_plane_atomic_check(struct drm_plane *plane,
906 struct drm_atomic_state *state)
907 {
908 struct drm_device *drm = plane->dev;
909 struct ssd130x_device *ssd130x = drm_to_ssd130x(drm);
910 struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state, plane);
911 struct ssd130x_plane_state *ssd130x_state = to_ssd130x_plane_state(plane_state);
912 struct drm_crtc *crtc = plane_state->crtc;
913 struct drm_crtc_state *crtc_state;
914 const struct drm_format_info *fi;
915 unsigned int pitch;
916 int ret;
917
918 if (crtc)
919 crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
crtc_state is not initialized
920
--> 921 ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
The rule here is that if drm_atomic_helper_check_plane_state() is
inlined then we have to examine it to see if "crtc_state" is used, but
since it's not inlined then passing uninitialized data is a bug
regardless of whether or not it's used. It will triger a KMsan warning
at runtime as well.
922 DRM_PLANE_NO_SCALING,
923 DRM_PLANE_NO_SCALING,
924 false, false);
925 if (ret)
926 return ret;
927 else if (!plane_state->visible)
928 return 0;
929
930 fi = drm_format_info(DRM_FORMAT_R8);
931 if (!fi)
regards,
dan carpenter
