diff --git a/.gitlab-ci/container/build-apitrace.sh b/.gitlab-ci/container/build-apitrace.sh
index f5c8a649af4..89233049b02 100644
--- a/.gitlab-ci/container/build-apitrace.sh
+++ b/.gitlab-ci/container/build-apitrace.sh
@@ -7,7 +7,7 @@
 # DEBIAN_TEST_VK_TAG
 # KERNEL_ROOTFS_TAG
 
-set -ex
+set -uex
 
 APITRACE_VERSION="0a6506433e1f9f7b69757b4e5730326970c4321a"
 
@@ -15,7 +15,7 @@ git clone https://github.com/apitrace/apitrace.git --single-branch --no-checkout
 pushd /apitrace
 git checkout "$APITRACE_VERSION"
 git submodule update --init --depth 1 --recursive
-cmake -S . -B _build -G Ninja -DCMAKE_BUILD_TYPE=Release -DENABLE_GUI=False -DENABLE_WAFFLE=on $EXTRA_CMAKE_ARGS
+cmake -S . -B _build -G Ninja -DCMAKE_BUILD_TYPE=Release -DENABLE_GUI=False -DENABLE_WAFFLE=on ${EXTRA_CMAKE_ARGS:-}
 cmake --build _build --parallel --target apitrace eglretrace
 mkdir build
 cp _build/apitrace build