diff --git a/.github/workflows/optional.yml b/.github/workflows/optional.yml
index 850b62b225..0cd82550f3 100644
--- a/.github/workflows/optional.yml
+++ b/.github/workflows/optional.yml
@@ -27,17 +27,21 @@ jobs:
       - run: docker run --rm --privileged multiarch/qemu-user-static:register --reset
       - uses: docker://multiarch/ubuntu-core:s390x-focal
         with:
+          # Docker runs the command as root, but we want the build/test to run
+          # as non-root so permissions based tests run correctly
           args: >
             bash -c
             "
             apt-get -y update &&
             DEBIAN_FRONTEND=noninteractive apt-get -y install build-essential cmake curl gettext ninja-build locales-all cpanminus git attr libattr1-dev  &&
-            git clone --depth=1 https://github.com/neovim/neovim.git &&
+            useradd --create-home qemuci &&
+            chown -R qemuci. . &&
+            runuser -u qemuci -- git clone --depth=1 https://github.com/neovim/neovim.git &&
             cd neovim &&
-            git fetch origin ${{ github.ref }}:pr &&
-            git switch pr &&
-            cmake -S cmake.deps -B .deps -G Ninja -D USE_BUNDLED_LUAJIT=OFF -D USE_BUNDLED_LUA=ON &&
-            cmake --build .deps &&
-            cmake -B build -G Ninja -D PREFER_LUA=ON &&
-            make ${{ matrix.test }}
+            runuser -u qemuci -- git fetch origin ${{ github.ref }}:pr &&
+            runuser -u qemuci -- git switch pr &&
+            runuser -u qemuci -- cmake -S cmake.deps -B .deps -G Ninja -D USE_BUNDLED_LUAJIT=OFF -D USE_BUNDLED_LUA=ON &&
+            runuser -u qemuci -- cmake --build .deps &&
+            runuser -u qemuci -- cmake -B build -G Ninja -D PREFER_LUA=ON &&
+            runuser -u qemuci -- make ${{ matrix.test }}
             "