--- a/js/public/Utility.h
+++ b/js/public/Utility.h
@@ -110,17 +110,17 @@ extern JS_PUBLIC_API(void) JS_Abort(void
  * In order to test OOM conditions, when the shell command-line option
  * |-A NUM| is passed, we fail continuously after the NUM'th allocation.
  */
 extern JS_PUBLIC_DATA(uint32_t) OOM_maxAllocations; /* set from shell/js.cpp */
 extern JS_PUBLIC_DATA(uint32_t) OOM_counter; /* data race, who cares. */
 #  define JS_OOM_POSSIBLY_FAIL() \
     do \
     { \
-        if (OOM_counter++ >= OOM_maxAllocations) { \
+        if (++OOM_counter > OOM_maxAllocations) { \
             return NULL; \
         } \
     } while (0)
 
 # else
 #  define JS_OOM_POSSIBLY_FAIL() do {} while(0)
 # endif