--- a/browser/app/macbuild/Contents/Info.plist.in
+++ b/browser/app/macbuild/Contents/Info.plist.in
@@ -220,16 +220,21 @@
 		</dict>
 	</array>
 	<key>CFBundleVersion</key>
 	<string>%MAC_BUNDLE_VERSION%</string>
 	<key>NSAppleScriptEnabled</key>
 	<true/>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.productivity</string>
+	<key>LSEnvironment</key>
+	<dict>
+		<key>MallocNanoZone</key>
+		<string>0</string>
+	</dict>
 	<key>LSFileQuarantineEnabled</key>
 	<true/>
 	<key>LSMinimumSystemVersion</key>
 	<string>10.9.0</string>
   <key>NSSupportsAutomaticGraphicsSwitching</key>
   <true/>
   <key>NSPrincipalClass</key>
   <string>GeckoNSApplication</string>

--- a/memory/build/zone.c
+++ b/memory/build/zone.c
@@ -415,16 +415,22 @@ register_zone(void)
   // the default zone when it is created for "small" allocations
   // (< 15 KiB), but assumes the default zone is a scalable_zone.  This
   // obviously fails when the default zone is the jemalloc zone, so
   // malloc_default_purgeable_zone is called beforehand so that the
   // default purgeable zone is created when the default zone is still
   // a scalable_zone.
   malloc_zone_t* purgeable_zone = malloc_default_purgeable_zone();
 
+  // There is a problem related to the above with the system nano zone, which
+  // is hard to work around from here, and that is instead worked around by
+  // disabling the nano zone through an environment variable
+  // (MallocNanoZone=0). In Firefox, we do that through
+  // browser/app/macbuild/Contents/Info.plist.in.
+
   // Register the custom zone.  At this point it won't be the default.
   malloc_zone_register(&zone);
 
   do {
     // Unregister and reregister the default zone.  On OSX >= 10.6,
     // unregistering takes the last registered zone and places it at the
     // location of the specified zone.  Unregistering the default zone thus
     // makes the last registered one the default.  On OSX < 10.6,