diff --git a/xserver/dix/pixmap.c b/xserver/dix/pixmap.c
index 6923e7e7b..061bd421d 100644
--- a/xserver/dix/pixmap.c
+++ b/xserver/dix/pixmap.c
@@ -117,7 +117,7 @@ AllocatePixmap(ScreenPtr pScreen, int pixDataSize)
     if (pScreen->totalPixmapSize > ((size_t) - 1) - pixDataSize)
         return NullPixmap;
 
-    pPixmap = malloc(pScreen->totalPixmapSize + pixDataSize);
+    pPixmap = calloc(1, pScreen->totalPixmapSize + pixDataSize);
     if (!pPixmap)
         return NullPixmap;