st/dri: Check for NULL before dereference and assignment.

diff --git a/src/gallium/state_trackers/dri/drm/dri1.c b/src/gallium/state_trackers/dri/drm/dri1.c
index bdf251653d9cde792c808b603a296a5b0df2d3d1..e216e46a87e6db478de3a3eba8125709d6a57900 100644 (file)
--- a/src/gallium/state_trackers/dri/drm/dri1.c
+++ b/src/gallium/state_trackers/dri/drm/dri1.c
@@ -89,10 +89,18 @@ dri1_propagate_drawable_change(struct dri_context *ctx)
 {
    __DRIdrawable *dPriv = ctx->dPriv;
    __DRIdrawable *rPriv = ctx->rPriv;
-   struct dri_drawable *draw = dri_drawable(dPriv);
-   struct dri_drawable *read = dri_drawable(rPriv);
+   struct dri_drawable *draw;
+   struct dri_drawable *read;
    boolean flushed = FALSE;
 
+   if (dPriv) {
+      draw = dri_drawable(dPriv);
+   }
+
+   if (rPriv) {
+      read = dri_drawable(rPriv);
+   }
+
    if (dPriv && draw->texture_stamp != dPriv->lastStamp) {
       ctx->st->flush(ctx->st, PIPE_FLUSH_RENDER_CACHE, NULL);
       flushed = TRUE;