diff --git a/hw/xwin/ChangeLog b/hw/xwin/ChangeLog
index 3d5bd1e83..e0970a7b0 100644
--- a/hw/xwin/ChangeLog
+++ b/hw/xwin/ChangeLog
@@ -1,3 +1,8 @@
+2005-01-08  Alexander Gottwald  <ago at freedesktop dot org>
+
+	* winblock.c:
+	Fix a possible null-pointer dereference	(Keishi Suenaga)
+
 2005-01-06  Alexander Gottwald  <ago at freedesktop dot org>
 
 	* Imakefile 
diff --git a/hw/xwin/winblock.c b/hw/xwin/winblock.c
index 37da595a7..1d21faf46 100644
--- a/hw/xwin/winblock.c
+++ b/hw/xwin/winblock.c
@@ -54,8 +54,11 @@ winBlockHandler (int nScreen,
   MSG			msg;
 #ifndef HAS_DEVWINDOWS
   struct timeval **tvp = pTimeout;
-  (*tvp)->tv_sec = 0;
-  (*tvp)->tv_usec = 100;
+  if (*tvp != NULL) 
+  {
+    (*tvp)->tv_sec = 0;
+    (*tvp)->tv_usec = 100;
+  }
 #endif
 
 #if defined(XWIN_CLIPBOARD) || defined(XWIN_MULTIWINDOW)