diff --git a/buildbot/master/files/config/environments.py b/buildbot/master/files/config/environments.py
index ee809d8c..d014a90f 100644
--- a/buildbot/master/files/config/environments.py
+++ b/buildbot/master/files/config/environments.py
@@ -75,6 +75,10 @@ def without(self, to_unset):
     'SHELL': '/bin/bash',
 })
 
+build_linux_rel_debug_assert = build_linux + Environment({
+    'SERVO_ENABLE_DEBUG_ASSERTIONS': '1',
+})
+
 build_android = build_linux + Environment({
     'ANDROID_NDK': '{{ common.servo_home }}/android/ndk/current/',
     'ANDROID_SDK': '{{ common.servo_home }}/android/sdk/current/',
diff --git a/buildbot/master/files/config/master.cfg b/buildbot/master/files/config/master.cfg
index 706a8d90..b531d47f 100644
--- a/buildbot/master/files/config/master.cfg
+++ b/buildbot/master/files/config/master.cfg
@@ -170,7 +170,8 @@ c['builders'] = [
     DynamicServoBuilder("arm64", CROSS_SLAVES, envs.build_arm64),
     DynamicServoBuilder("linux-dev", LINUX_SLAVES, envs.build_linux),
     DynamicServoBuilder("linux-nightly", LINUX_SLAVES, envs.build_linux),
-    DynamicServoBuilder("linux-rel", LINUX_SLAVES, envs.build_linux),
+    DynamicServoBuilder("linux-rel", LINUX_SLAVES,
+                        envs.build_linux_rel_debug_assert),
     DynamicServoBuilder("linux-rel-intermittent", LINUX_SLAVES,
                         envs.build_linux),
     DynamicServoBuilder("mac-dev-unit", MAC_SLAVES, envs.build_mac),