[PATCH 2/4] drm/i915: fix uninitialized pointer reads on pointers to and from

[Sultan Alsawaf]

From: Colin Ian King <colin.king at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1868551

Currently pointers to and from are not initialized and may contain
garbage values. This will cause uninitialized pointer reads in the
call to intel_frontbuffer_track and later checks to see if to and from
are null.  Fix this by ensuring to and from are initialized to NULL.

Addresses-Coverity: ("Uninitialised pointer read)"
Fixes: da42104f589d ("drm/i915: Hold reference to intel_frontbuffer as we track activity")
Signed-off-by: Colin Ian King <colin.king at canonical.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191219190916.24693-1-colin.king@canonical.com
(cherry picked from commit e1f0fbda75e6447077205b472d1dd71bef417a4c)
Signed-off-by: Sultan Alsawaf <sultan.alsawaf at canonical.com>
---
 drivers/gpu/drm/i915/display/intel_overlay.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index 59f836dc00eb..c754be02c1cc 100644
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -278,7 +278,7 @@ static void intel_overlay_flip_prepare(struct intel_overlay *overlay,
 				       struct i915_vma *vma)
 {
 	enum pipe pipe = overlay->crtc->pipe;
-	struct intel_frontbuffer *from, *to;
+	struct intel_frontbuffer *from = NULL, *to = NULL;
 
 	WARN_ON(overlay->old_vma);
 
-- 
2.20.1