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ci: lower mmap_rnd_bits for address and thread sanitizer jobs - #957
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viferga merged 2 commits intoNov 12, 2026
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ubuntu-latest moved to ubuntu-26.04, and its kernel uses more mmap random bits than the sanitizers support, so every thread sanitizer test dies at startup with "unexpected memory mapping". The setting belongs to the host kernel and docker containers can not change it, so set vm.mmap_rnd_bits=28 on the runner before the tests start. Only the GCC sanitizer jobs and the clang address and thread sanitizer jobs get it.
bhuvan-somisetty
changed the title
Check for the address and thread sanitizer entries explicitly, so a new entry added to the clang matrix does not get the sysctl by accident.
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Motive
The thread sanitizer jobs started failing on every test with "unexpected memory mapping".
ubuntu-latestmoved to ubuntu-26.04, and the newer kernel uses more mmap random bits than the sanitizers support. The last green run was still on 24.04.Approach
vm.mmap_rnd_bitsis a host kernel setting, and docker containers share the host kernel and can not write/proc/sys, so it can not go inmetacall-environment.sh. This adds a step that runssudo sysctl vm.mmap_rnd_bits=28on the runner before./docker-compose.sh:linux-sanitizer-test: always, since every entry is address or thread sanitizerlinux-clang-test: only forclang-address-sanitizerandclang-thread-sanitizer(named explicitly in theif)The memory sanitizer and valgrind jobs are unchanged. Scope agreed with @viferga on Discord: only when running with thread or address sanitizer.
Tests
Can not be run locally, the CI run on this PR is the test. The thread and address sanitizer jobs should get past startup again.
AI-ASSISTED: yes, model: Claude Opus 5.5, human reviewer: bhuvan-somisetty