diff --git a/js/src/tests/js1_5/extensions/jstests.list b/js/src/tests/js1_5/extensions/jstests.list
index c106462869c..71dd63578ef 100644
--- a/js/src/tests/js1_5/extensions/jstests.list
+++ b/js/src/tests/js1_5/extensions/jstests.list
@@ -45,7 +45,7 @@ skip script regress-330569.js # Yarr doesn't bail on complex regexps.
 script regress-333541.js
 skip script regress-335700.js # bug xxx - reftest hang, BigO
 skip-if(!xulRuntime.shell) script regress-336409-1.js # no results reported.
-skip-if(!xulRuntime.shell&&xulRuntime.XPCOMABI.match(/x86_64/)) silentfail script regress-336409-2.js # can fail silently due to out of memory
+skip-if(!xulRuntime.shell&&((isDebugBuild&&xulRuntime.OS=="Linux")||xulRuntime.XPCOMABI.match(/x86_64/))) silentfail script regress-336409-2.js # can fail silently due to out of memory, bug 615011 - timeouts on slow debug Linux
 skip-if(!xulRuntime.shell) silentfail script regress-336410-1.js # can fail silently due to out of memory
 skip-if(!xulRuntime.shell&&(xulRuntime.XPCOMABI.match(/x86_64/)||xulRuntime.OS=="WINNT")) silentfail script regress-336410-2.js # can fail silently due to out of memory
 script regress-338804-01.js