glx: Prevent potential null pointer deference in driCreateContext.

(cherry picked from commit 4b0b250aae6ae7d48cd24f9d91d05ab58086c4b2)

diff --git a/src/glx/x11/drisw_glx.c b/src/glx/x11/drisw_glx.c
index 15e1586..1866b2c 100644 (file)
--- a/src/glx/x11/drisw_glx.c
+++ b/src/glx/x11/drisw_glx.c
@@ -250,12 +250,14 @@ driCreateContext(__GLXscreenConfigs * psc,
 {
    __GLXDRIcontextPrivate *pcp, *pcp_shared;
    __GLXDRIconfigPrivate *config = (__GLXDRIconfigPrivate *) mode;
-   const __DRIcoreExtension *core = psc->core;
+   const __DRIcoreExtension *core;
    __DRIcontext *shared = NULL;
 
    if (!psc || !psc->driScreen)
       return NULL;
 
+   core = psc->core;
+
    if (shareList) {
       pcp_shared = (__GLXDRIcontextPrivate *) shareList->driContext;
       shared = pcp_shared->driContext;