--- a/testing/taskcluster/scripts/builder/build-linux.sh
+++ b/testing/taskcluster/scripts/builder/build-linux.sh
@@ -40,19 +40,21 @@ export MOZ_SIMPLE_PACKAGE_NAME=target
 # Ensure that in tree libraries can be found
 export LIBRARY_PATH=$LIBRARY_PATH:$WORKSPACE/src/obj-firefox:$WORKSPACE/src/gcc/lib64
 
 # test required parameters are supplied
 if [[ -z ${MOZHARNESS_SCRIPT} ]]; then exit 1; fi
 if [[ -z ${MOZHARNESS_CONFIG} ]]; then exit 1; fi
 
 cleanup() {
+    local rv=$?
     if [ -n "$xvfb_pid" ]; then
         kill $xvfb_pid || true
     fi
+    exit $rv
 }
 trap cleanup EXIT INT
 
 # run mozharness in XVfb, if necessary; this is an array to maintain the quoting in the -s argument
 if $NEED_XVFB; then
     # Some mozharness scripts set DISPLAY=:2
     Xvfb :2 -screen 0 1024x768x24 &
     export DISPLAY=:2