dri: Fix potential null pointer deference in dri_put_drawable.

(cherry picked from commit 364070b1f2b08d43fb205ec198894a35bec6b2f3)

diff --git a/src/mesa/drivers/dri/common/dri_util.c b/src/mesa/drivers/dri/common/dri_util.c
index e48e10d7c061f6e73ea70cbf4bcbe689e92e2ef9..439f66a7b882de1c996b1ea271c84e129788a6c0 100644 (file)
--- a/src/mesa/drivers/dri/common/dri_util.c
+++ b/src/mesa/drivers/dri/common/dri_util.c
@@ -498,11 +498,11 @@ static void dri_put_drawable(__DRIdrawable *pdp)
 {
     __DRIscreenPrivate *psp;
 
-    pdp->refcount--;
-    if (pdp->refcount)
-       return;
-
     if (pdp) {
+       pdp->refcount--;
+       if (pdp->refcount)
+           return;
+
        psp = pdp->driScreenPriv;
         (*psp->DriverAPI.DestroyBuffer)(pdp);
        if (pdp->pClipRects) {