--- a/hal/gonk/GonkDiskSpaceWatcher.cpp
+++ b/hal/gonk/GonkDiskSpaceWatcher.cpp
@@ -164,16 +164,19 @@ GonkDiskSpaceWatcher::DoStart()
   NS_ASSERTION(XRE_GetIOMessageLoop() == MessageLoopForIO::current(),
                "Not on the correct message loop");
 
   mFd = fanotify_init(FAN_CLASS_NOTIF, FAN_CLOEXEC);
   if (mFd == -1) {
     NS_WARNING("Error calling inotify_init()");
     if (errno == ENOSYS) {
       NS_WARNING("Warning: No fanotify support in this device's kernel.\n");
+#if ANDROID_VERSION >= 19
+      MOZ_CRASH("Fanotify support must be enabled in the kernel.");
+#endif
     }
     return;
   }
 
   if (fanotify_mark(mFd, FAN_MARK_ADD | FAN_MARK_MOUNT, FAN_CLOSE,
                     0, kWatchedPath) < 0) {
     NS_WARNING("Error calling fanotify_mark");
     close(mFd);