[PATCH 73/73] ci: Add Linux kernel GitHub Actions workflow and build script

[Bart Van Assche <bvanassche@acm.org>]

Add a GitHub Actions workflow and helper script to build the Linux
kernel with sparse under AddressSanitizer and UndefinedBehaviorSanitizer
so regressions not covered by the validation suite are caught on a large
real-world C codebase:
- .github/workflows/build-linux-kernel-with-sparse.yml: Run on push,
  pull_request, daily schedule, and workflow_dispatch with read-only
  repository contents permissions.
- ci/build-linux-kernel-with-sparse.sh: Clean and build sparse in asan
  mode, clone ../linux-kernel or upstream torvalds/linux.git, neutralize
  non-core __CHECKER__ guards, and run a defconfig C=1 kernel check with
  detect_invalid_pointer_pairs=2 and halt_on_error=1.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 .../build-linux-kernel-with-sparse.yml        | 28 +++++++++++++++++++
 ci/build-linux-kernel-with-sparse.sh          | 23 +++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100644 .github/workflows/build-linux-kernel-with-sparse.yml
 create mode 100755 ci/build-linux-kernel-with-sparse.sh

diff --git a/.github/workflows/build-linux-kernel-with-sparse.yml b/.github/workflows/build-linux-kernel-with-sparse.yml
new file mode 100644
index 000000000000..a7566c4d8082
--- /dev/null
+++ b/.github/workflows/build-linux-kernel-with-sparse.yml
@@ -0,0 +1,28 @@
+# See also https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+
+name: Build Linux kernel with sparse
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@main
+
+    - name: install
+      run: sudo ci/install.sh
+
+    - name: build Linux kernel with sparse
+      run: |
+        sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc
+        ci/build-linux-kernel-with-sparse.sh
diff --git a/ci/build-linux-kernel-with-sparse.sh b/ci/build-linux-kernel-with-sparse.sh
new file mode 100755
index 000000000000..7e3505634d95
--- /dev/null
+++ b/ci/build-linux-kernel-with-sparse.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -euo pipefail
+
+make clean
+export MODE=asan
+ci/build.sh
+
+rm -rf linux-kernel
+if [ -e ../linux-kernel ]; then
+    git clone ../linux-kernel linux-kernel
+else
+    git clone --depth=3 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux-kernel
+fi
+cd linux-kernel
+# Make most __CHECKER__ checks ineffective.
+{ git grep -lw __CHECKER__ || [ $? -eq 1 ]; } |
+    { grep -vE '^arch/|^include/linux/compiler|^include/uapi/linux/types.h|^include/linux/bug.h' || [ $? -eq 1 ]; } |
+    xargs -r -d '\n' sed -i 's/__CHECKER__/___CHECKER___/g'
+make defconfig
+export ASAN_OPTIONS=detect_invalid_pointer_pairs=2
+export UBSAN_OPTIONS=halt_on_error=1
+make -sj"$(nproc)" C=1 CHECK="${PWD}/../sparse"