[Mesa-stable] [PATCH 2/2] glx/dri3: handle NULL pointers in loader-to-DRI3 drawable conversion

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

With the previous patch, we can now get NULL loaderPrivates, e.g. when
a DRIdrawable is flushed whose corresponding GLXDRIdrawable was destroyed.
This resulted in a crash, since the loader vs. DRI3 drawable structures
have a non-zero offset.

Fixes glx-visuals-depth/stencil -pixmap

Cc: 17.0 <mesa-stable at lists.freedesktop.org>
---
 src/glx/dri3_glx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c
index 4472a0b..f7bcba3 100644
--- a/src/glx/dri3_glx.c
+++ b/src/glx/dri3_glx.c
@@ -74,20 +74,22 @@
 #include <sys/time.h>
 
 #include "dri_common.h"
 #include "dri3_priv.h"
 #include "loader.h"
 #include "dri2.h"
 
 static struct dri3_drawable *
 loader_drawable_to_dri3_drawable(struct loader_dri3_drawable *draw) {
    size_t offset = offsetof(struct dri3_drawable, loader_drawable);
+   if (!draw)
+      return NULL;
    return (struct dri3_drawable *)(((void*) draw) - offset);
 }
 
 static int
 glx_dri3_get_swap_interval(struct loader_dri3_drawable *draw)
 {
    struct dri3_drawable *priv = loader_drawable_to_dri3_drawable(draw);
 
    return priv->swap_interval;
 }
-- 
2.7.4