--- src/gallium/auxiliary/pipebuffer/pb_buffer.h.ORIGINAL	2016-02-10 18:57:54.000000000 -0500
+++ src/gallium/auxiliary/pipebuffer/pb_buffer.h	2016-03-24 22:40:19.737680000 -0400
@@ -238,7 +238,7 @@ pb_reference(struct pb_buffer **dst,
 {
    struct pb_buffer *old = *dst;
 
-   if (pipe_reference(&(*dst)->reference, &src->reference))
+   if (pipe_reference(&(*dst)->reference, (src ? &src->reference : NULL)))
       pb_destroy( old );
    *dst = src;
 }