diff --git a/.buildkite/scripts/ci-otel/ci_otel.sh b/.buildkite/scripts/ci-otel/ci_otel.sh
index c9897e732e..7f1b700fe6 100755
--- a/.buildkite/scripts/ci-otel/ci_otel.sh
+++ b/.buildkite/scripts/ci-otel/ci_otel.sh
@@ -65,6 +65,39 @@ _ci_otel_python() {
   fi
 }
 
+# The Docker test commands run as root, while /workdir is owned by the
+# Buildkite checkout user. Run the GPU sampler as that unprivileged identity so
+# any future project-code import cannot leave root-owned files in the checkout.
+_ci_otel_prepare_gpu_user() {
+  _CI_INFRA_GPU_UID=""
+  _CI_INFRA_GPU_GID=""
+  [ "$(id -u 2>/dev/null || :)" = "0" ] || return 0
+  command -v setpriv >/dev/null 2>&1 || return 1
+
+  _CI_INFRA_OTEL_WORKSPACE_DIR="${CI_INFRA_OTEL_WORKSPACE_DIR:-/workdir}"
+  [ -d "${_CI_INFRA_OTEL_WORKSPACE_DIR}" ] || return 1
+  # The owner fields are numeric and whitespace-free on GNU stat.
+  # shellcheck disable=SC2046
+  set -- $(stat -c '%u %g' -- "${_CI_INFRA_OTEL_WORKSPACE_DIR}" 2>/dev/null || :)
+  [ "$#" -eq 2 ] || return 1
+  case "$1:$2" in
+    *[!0-9:]* | 0:* | *:0) return 1 ;;
+  esac
+
+  _CI_INFRA_GPU_UID="$1"
+  _CI_INFRA_GPU_GID="$2"
+  chown "${_CI_INFRA_GPU_UID}:${_CI_INFRA_GPU_GID}" \
+    "${CI_INFRA_OTEL_SPOOL_DIR}" || return 1
+  chmod 0700 "${CI_INFRA_OTEL_SPOOL_DIR}" || return 1
+  if [ "${_CI_INFRA_OTEL_OWNS_RUNTIME}" = "1" ]; then
+    # Permit traversal to the private child spool, but not directory listing.
+    chmod 0711 "${CI_INFRA_OTEL_RUNTIME_DIR}" || return 1
+  fi
+  setpriv --reuid="${_CI_INFRA_GPU_UID}" \
+    --regid="${_CI_INFRA_GPU_GID}" --clear-groups --no-new-privs \
+    -- test -w "${CI_INFRA_OTEL_SPOOL_DIR}"
+}
+
 ci_otel_start() {
   _CI_INFRA_OTEL_COMMAND_INDEX="$1"
   _CI_INFRA_OTEL_COMMAND_LABEL="${2:-command ${_CI_INFRA_OTEL_COMMAND_INDEX}}"
@@ -87,9 +120,23 @@ ci_otel_start() {
   if [ "${CI_INFRA_GPU_SAMPLING:-1}" != "0" ] &&
     [ -f "${CI_INFRA_OTEL_DIR}/ci_gpu.py" ] &&
     command -v nvidia-smi >/dev/null 2>&1; then
-    PYTHONDONTWRITEBYTECODE=1 \
-      "${_CI_INFRA_OTEL_PYTHON}" "${CI_INFRA_OTEL_DIR}/ci_gpu.py" "$$" </dev/null &
-    _CI_INFRA_GPU_PID=$!
+    if _ci_otel_prepare_gpu_user; then
+      if [ -n "${_CI_INFRA_GPU_UID}" ]; then
+        PYTHONDONTWRITEBYTECODE=1 setpriv \
+          --reuid="${_CI_INFRA_GPU_UID}" --regid="${_CI_INFRA_GPU_GID}" \
+          --clear-groups --no-new-privs -- \
+          "${_CI_INFRA_OTEL_PYTHON}" "${CI_INFRA_OTEL_DIR}/ci_gpu.py" "$$" \
+          </dev/null &
+      else
+        PYTHONDONTWRITEBYTECODE=1 \
+          "${_CI_INFRA_OTEL_PYTHON}" "${CI_INFRA_OTEL_DIR}/ci_gpu.py" "$$" \
+          </dev/null &
+      fi
+      _CI_INFRA_GPU_PID=$!
+    else
+      echo "vLLM CI OTel: non-root GPU sampler unavailable; sampling disabled" \
+        >&2 || :
+    fi
   fi
 }
 
diff --git a/.buildkite/scripts/ci-otel/tests/test_ci_otel.py b/.buildkite/scripts/ci-otel/tests/test_ci_otel.py
index ae51010f9e..c66530989f 100644
--- a/.buildkite/scripts/ci-otel/tests/test_ci_otel.py
+++ b/.buildkite/scripts/ci-otel/tests/test_ci_otel.py
@@ -987,6 +987,85 @@ def test_gpu_periodic_batches_are_bounded_even_when_upload_fails(monkeypatch):
     assert [len(batch[0].events) for batch in batches] == [1, 1, 1]
 
 
+def _write_executable(path: Path, body: str) -> None:
+    path.write_text(f"#!/bin/sh\n{body}")
+    path.chmod(0o755)
+
+
+@pytest.mark.parametrize(
+    "workspace_owner,expect_sampler",
+    [("997 996", True), ("0 0", False)],
+)
+def test_root_shell_runs_gpu_sampler_as_checkout_owner(
+    tmp_path, workspace_owner, expect_sampler
+):
+    bin_dir = tmp_path / "bin"
+    workspace = tmp_path / "workdir"
+    runtime = tmp_path / "runtime"
+    log = tmp_path / "calls.log"
+    bin_dir.mkdir()
+    workspace.mkdir()
+
+    _write_executable(
+        bin_dir / "id",
+        '[ "$1" = "-u" ] && { echo 0; exit 0; }; exec /usr/bin/id "$@"\n',
+    )
+    _write_executable(
+        bin_dir / "stat",
+        f"printf '%s\\n' '{workspace_owner}'\n",
+    )
+    for command in ("chown", "chmod"):
+        _write_executable(bin_dir / command, "exit 0\n")
+    _write_executable(
+        bin_dir / "setpriv",
+        'printf "setpriv %s\\n" "$*" >> "$CI_OTEL_TEST_LOG"\n'
+        'while [ "$#" -gt 0 ] && [ "$1" != "--" ]; do shift; done\n'
+        '[ "$#" -gt 0 ] && shift\n'
+        'exec "$@"\n',
+    )
+    _write_executable(
+        bin_dir / "python3",
+        '[ "$1" = "-c" ] && exit 0\n'
+        '[ "$2" = "new-context" ] && {\n'
+        '  echo "01010101010101010101010101010101 0202020202020202 - 1"\n'
+        "  exit 0\n"
+        "}\n"
+        'case "$1" in *ci_gpu.py) echo gpu >> "$CI_OTEL_TEST_LOG";; esac\n'
+        "exit 0\n",
+    )
+    _write_executable(bin_dir / "nvidia-smi", "exit 0\n")
+    shell = (
+        f'. "{SCRIPTS_DIR / "ci_otel.sh"}"; '
+        f"ci_otel_start 1 {_quoted('true')}; ci_otel_finish 0"
+    )
+
+    result = subprocess.run(
+        ["/bin/sh", "-c", shell],
+        check=False,
+        capture_output=True,
+        text=True,
+        env={
+            **os.environ,
+            "PATH": f"{bin_dir}:{os.environ['PATH']}",
+            "CI_INFRA_OTEL_DIR": str(SCRIPTS_DIR),
+            "CI_INFRA_OTEL_RUNTIME_DIR": str(runtime),
+            "CI_INFRA_OTEL_WORKSPACE_DIR": str(workspace),
+            "CI_OTEL_TEST_LOG": str(log),
+        },
+    )
+
+    assert result.returncode == 0, result.stderr
+    calls = log.read_text() if log.exists() else ""
+    if expect_sampler:
+        expected = "--reuid=997 --regid=996 --clear-groups --no-new-privs --"
+        assert calls.count("setpriv") == 2
+        assert calls.count(expected) == 2
+        assert "gpu" in calls
+    else:
+        assert calls == ""
+        assert "non-root GPU sampler unavailable" in result.stderr
+
+
 @pytest.mark.parametrize("sampling", ["1", "0"])
 def test_gpu_sampler_stops_with_command_and_preserves_failure_status(
     tmp_path, sampling