diff --git a/dom/settings/SettingsManager.js b/dom/settings/SettingsManager.js
index 0a3854f38a1..9de0953c44a 100644
--- a/dom/settings/SettingsManager.js
+++ b/dom/settings/SettingsManager.js
@@ -39,6 +39,8 @@ XPCOMUtils.defineLazyServiceGetter(this, "uuidgen",
                                    "@mozilla.org/uuid-generator;1",
                                    "nsIUUIDGenerator");
 
+const kObserverSoftLimit = 10;
+
 /**
  * In order to make SettingsManager work with Privileged Apps, we need the lock
  * to be OOP. However, the lock state needs to be managed on the child process,
@@ -363,14 +365,26 @@ SettingsManager.prototype = {
 
   addObserver: function addObserver(aName, aCallback) {
     if (VERBOSE) debug("addObserver " + aName);
+
     if (!this._callbacks) {
       this._callbacks = {};
     }
+
     if (!this._callbacks[aName]) {
       this._callbacks[aName] = [aCallback];
     } else {
       this._callbacks[aName].push(aCallback);
     }
+
+    let length = this._callbacks[aName].length;
+    if (length >= kObserverSoftLimit) {
+      debug("WARNING: MORE THAN " + kObserverSoftLimit + " OBSERVERS FOR " +
+            aName + ": " + length + " FROM" + (new Error).stack);
+#ifdef DEBUG
+      throw Components.results.NS_ERROR_ABORT;
+#endif
+    }
+
     this.checkMessageRegistration();
   },
 
@@ -421,7 +435,7 @@ SettingsManager.prototype = {
       }
 
       let path;
-      if (length < 20) {
+      if (length < kObserverSoftLimit) {
         path = "settings-observers";
       } else {
         path = "settings-observers-suspect/referent(topic=" +
diff --git a/dom/settings/moz.build b/dom/settings/moz.build
index 10a6055ba12..0588a22419d 100644
--- a/dom/settings/moz.build
+++ b/dom/settings/moz.build
@@ -5,8 +5,11 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 EXTRA_COMPONENTS += [
-    'SettingsManager.js',
-    'SettingsManager.manifest',
+    'SettingsManager.manifest'
+]
+
+EXTRA_PP_COMPONENTS += [
+    'SettingsManager.js'
 ]
 
 if CONFIG['MOZ_B2G']:
diff --git a/dom/settings/tests/mochitest.ini b/dom/settings/tests/mochitest.ini
index 87e3c3be926..b57f821d93f 100644
--- a/dom/settings/tests/mochitest.ini
+++ b/dom/settings/tests/mochitest.ini
@@ -12,4 +12,6 @@ support-files =
 [test_settings_navigator_object.html]
 [test_settings_onsettingchange.html]
 [test_settings_bug1110872.html]
-skip-if = !e10s
\ No newline at end of file
+skip-if = !e10s
+[test_settings_observer_killer.html]
+skip-if = !debug
diff --git a/dom/settings/tests/test_settings_observer_killer.html b/dom/settings/tests/test_settings_observer_killer.html
new file mode 100644
index 00000000000..462515b10aa
--- /dev/null
+++ b/dom/settings/tests/test_settings_observer_killer.html
@@ -0,0 +1,68 @@
+<!DOCTYPE html>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1193469
+-->
+<head>
+  <title>Test for Bug 1193469 Settings API</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1193469">Mozilla Bug 1193469</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+<iframe></iframe>
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript;version=1.7">
+
+var url = SimpleTest.getTestFileURL("file_loadserver.js");
+var script = SpecialPowers.loadChromeScript(url);
+
+SimpleTest.waitForExplicitFinish();
+
+SpecialPowers.pushPermissions([
+  {type: "settings-api-read", allow: 1, context: document},
+  {type: "settings-api-write", allow: 1, context: document},
+  {type: "settings-read", allow: 1, context: document},
+  {type: "settings-write", allow: 1, context: document},
+  {type: "settings-clear", allow: 1, context: document}
+], function() {
+  SpecialPowers.pushPrefEnv({
+    set: [["dom.mozSettings.enabled", true]]
+  },
+    function () {
+      ok(true, "abusing observers");
+
+      var obs;
+      for (obs = 0; obs < 9; obs++) {
+        navigator.mozSettings.addObserver("fake.setting.key", function(v) {
+          // nothing to do for real ...
+          ok(false, "should not be called");
+        });
+        ok(true, "first: added observer #" + obs);
+      }
+      ok(true, "adding first observers, should not have thrown");
+
+      try {
+        ok(true, "second: adding new observer");
+        navigator.mozSettings.addObserver("fake.setting.key", function(v) {
+          // nothing to do for real ...
+          ok(false, "should not be called");
+        });
+        ok(false, "adding too many observers should have thrown");
+      } catch (ex) {
+        ok(true, "got exception when trying to add too many observers");
+      }
+
+      SimpleTest.finish();
+    });
+});
+
+</script>
+</pre>
+</body>
+</html>
