comment to explain why the fix is needed

.github/workflows/test.yml

@@ -297,6 +297,11 @@ jobs:
         CMAKE_PARAMS: ${{ matrix.params }}
         BUILD_TYPE: debug
         LSAN_OPTIONS: 'exitcode=42' #Use a non-standard exit code to ensure LSAN errors are detected
+        # In Ubuntu 20240310.1.0, the entropy of ASLR has increased (28 -> 32). LLVM 14 in this
+        # image is not compatible with this increased ASLR entropy. Apparently, memory sanitizer
+        # depends on LLVM and all CI tests where VTR_ENABLE_SANITIZE is enabled fail. For a temporary
+        # fix, we manually reduce the entropy. This quick fix should be removed in the future
+        # when github deploys a more stable Ubuntu image.
       run: |
         sudo sysctl -w vm.mmap_rnd_bits=28
         export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"