drm: Use drm_mode_init() for on-stack modes

Initialize on-stack modes with drm_mode_init() to guarantee
no stack garbage in the list head, or that we aren't copying
over another mode's list head.

Based on the following cocci script, with manual fixups:
@decl@
identifier M;
expression E;
@@
- struct drm_display_mode M = E;
+ struct drm_display_mode M;

@@
identifier decl.M;
expression decl.E;
statement S, S1;
@@
struct drm_display_mode M;
... when != S
+ drm_mode_init(&M, &E);
+
S1

@@
expression decl.E;
@@
- &*E
+ E

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220218100403.7028-22-ville.syrjala@linux.intel.com
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 04e818ecd662..dbca588474c3 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3551,9 +3551,11 @@ static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_m
 		match_flags |= DRM_MODE_MATCH_ASPECT_RATIO;
 
 	for (vic = 1; vic < cea_num_vics(); vic = cea_next_vic(vic)) {
-		struct drm_display_mode cea_mode = *cea_mode_for_vic(vic);
+		struct drm_display_mode cea_mode;
 		unsigned int clock1, clock2;
 
+		drm_mode_init(&cea_mode, cea_mode_for_vic(vic));
+
 		/* Check both 60Hz and 59.94Hz */
 		clock1 = cea_mode.clock;
 		clock2 = cea_mode_alternate_clock(&cea_mode);
@@ -3590,9 +3592,11 @@ u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
 		match_flags |= DRM_MODE_MATCH_ASPECT_RATIO;
 
 	for (vic = 1; vic < cea_num_vics(); vic = cea_next_vic(vic)) {
-		struct drm_display_mode cea_mode = *cea_mode_for_vic(vic);
+		struct drm_display_mode cea_mode;
 		unsigned int clock1, clock2;
 
+		drm_mode_init(&cea_mode, cea_mode_for_vic(vic));
+
 		/* Check both 60Hz and 59.94Hz */
 		clock1 = cea_mode.clock;
 		clock2 = cea_mode_alternate_clock(&cea_mode);