Index: Include/pymem.h
===================================================================
--- Include/pymem.h	(revision 697)
+++ Include/pymem.h	(working copy)
@@ -78,8 +78,8 @@
 
 #include "dlmalloc.h"
 
-#define PyMem_MALLOC(n)         dlmalloc((n))
-#define PyMem_REALLOC(p, n)     dlrealloc((p), (n))
+#define PyMem_MALLOC(n)         dlmalloc((n) ? (n) : 1)
+#define PyMem_REALLOC(p, n)     dlrealloc((p), (n) ? (n) : 1)
 #define PyMem_FREE		dlfree
 
 #endif /* WITH_DLMALLOC */
Index: Objects/obmalloc.c
===================================================================
--- Objects/obmalloc.c	(revision 697)
+++ Objects/obmalloc.c	(working copy)
@@ -976,9 +976,9 @@
 	 * last chance to serve the request) or when the max memory limit
 	 * has been reached.
 	 */
-#ifndef WITH_DLMALLOC
 	if (nbytes == 0)
 		nbytes = 1;
+#ifndef WITH_DLMALLOC
 	return (void *)malloc(nbytes);
 #else
 	return (void *)dlmalloc(nbytes);
@@ -1262,19 +1262,22 @@
 	 * a memory fault can occur if we try to copy nbytes bytes starting
 	 * at p.  Instead we punt:  let C continue to manage this block.
          */
+	if (nbytes)
 #ifndef WITH_DLMALLOC
-	if (nbytes)
-		return realloc(p, nbytes);
+   	    return realloc(p, nbytes);
+#else
+	    return dlrealloc(p, nbytes);
+#endif
 	/* C doesn't define the result of realloc(p, 0) (it may or may not
 	 * return NULL then), but Python's docs promise that nbytes==0 never
 	 * returns NULL.  We don't pass 0 to realloc(), to avoid that endcase
 	 * to begin with.  Even then, we can't be sure that realloc() won't
 	 * return NULL.
 	 */
+#ifndef WITH_DLMALLOC
 	bp = realloc(p, 1);
 #else
-	/* dlrealloc promises it won't return NULL for nbytes == 0 */
-	bp = dlrealloc(p, nbytes);
+	bp = dlrealloc(p, 1);
 #endif
 
    	return bp ? bp : p;