diff --git a/test/simple/test-child-process-fork-exec-argv.js b/test/simple/test-child-process-fork-exec-argv.js
index 1f9f89fbbb7e03..d0da341c247fe1 100644
--- a/test/simple/test-child-process-fork-exec-argv.js
+++ b/test/simple/test-child-process-fork-exec-argv.js
@@ -31,7 +31,7 @@ if (process.argv[2] === 'fork') {
 } else if (process.argv[2] === 'child') {
   fork(__filename, ['fork']);
 } else {
-  var execArgv = ['--harmony_proxies', '--stack-size=64'];
+  var execArgv = ['--harmony_proxies', '--stack-size=256'];
   var args = [__filename, 'child', 'arg0'];
 
   var child = spawn(process.execPath, execArgv.concat(args));
diff --git a/test/simple/test-process-exec-argv.js b/test/simple/test-process-exec-argv.js
index 3d845038957183..395753b72a9bdc 100644
--- a/test/simple/test-process-exec-argv.js
+++ b/test/simple/test-process-exec-argv.js
@@ -25,7 +25,7 @@ var spawn = require('child_process').spawn;
 if (process.argv[2] === 'child') {
   process.stdout.write(JSON.stringify(process.execArgv));
 } else {
-  var execArgv = ['--harmony_proxies', '--stack-size=64'];
+  var execArgv = ['--harmony_proxies', '--stack-size=256'];
   var args = [__filename, 'child', 'arg0'];
   var child = spawn(process.execPath, execArgv.concat(args));
   var out = '';