ci: run memtrack bpf tests across the kernel and arch matrix

Run the rss/bpf tests on arm and codspeed-macro runners over old- and
new-layout kernels.

Author: not-matthias

.github/workflows/ci.yml

@@ -88,22 +88,35 @@ jobs:
         run: cargo run -- exec -m walltime --skip-upload --warmup-time 0s --max-rounds 5 -- ls -la
 
   bpf-tests:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
+        os: [ubuntu-latest, ubuntu-24.04-arm, codspeed-macro]
         # Each memtrack integration test binary runs its cases serially
         # (eBPF tracker can't overlap with itself in one process), so we
         # shard at the test-binary level to parallelize across jobs.
-        test: [c_tests, cpp_tests, rust_tests, spawn_tests, dlopen_tests]
+        test: [c_tests, cpp_tests, rust_tests, spawn_tests, dlopen_tests, rss_tests]
+        include:
+          # The folio CO-RE relocations in the rmap hooks depend on kernel
+          # struct layouts that changed across versions (folio.flags in 6.18,
+          # pageflags values in 6.10/6.12); keep older-kernel images in the
+          # matrix so the legacy layouts stay covered once the latest images
+          # move past them.
+          - os: ubuntu-22.04
+            test: rss_tests
+          - os: ubuntu-22.04-arm
+            test: rss_tests
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           lfs: true
           submodules: true
+      - name: Show kernel version
+        run: uname -rm
       - uses: ./.github/actions/install-rust
         with:
-          cache-key: ${{ matrix.test }}
+          cache-key: ${{ matrix.os }}-${{ matrix.test }}
       - uses: ./.github/actions/install-bpf-deps
 
       - name: Install additional allocators
@@ -115,8 +128,11 @@ jobs:
         run: sudo -E $(which cargo) test --lib --test ${{ matrix.test }} -- --test-threads 1 --nocapture
         working-directory: crates/memtrack
 
-      # Since we ran the tests with sudo, the build artifacts will have root ownership
+      # Since we ran the tests with sudo, the build artifacts will have root
+      # ownership; always restore it so a failed run cannot poison the
+      # workspace of later jobs on persistent self-hosted runners.
       - name: Clean up
+        if: always()
         run: sudo chown -R $USER:$USER . ~/.cargo
 
   benchmarks: