FIX: run Debian ARM64 CI on preinstalled-python image to avoid QEMU segfault - #721
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Jahnvi Thakkar (jahnvi480) wants to merge 5 commits into
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FIX: run Debian ARM64 CI on preinstalled-python image to avoid QEMU segfault#721Jahnvi Thakkar (jahnvi480) wants to merge 5 commits into
Jahnvi Thakkar (jahnvi480) wants to merge 5 commits into
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The Linux ARM64 legs run under QEMU user-mode emulation on x86_64 agents. Older QEMU (multiarch/qemu-user-static) mishandles glibc restartable sequences (rseq), randomly SIGSEGV-ing (exit 139) the emulated arm64 Python during Debian's apt byte-compilation and forcing repeated job reruns (build 166395's Debian_ARM64 job needed 5 attempts). Two independent, root-cause guards scoped to the flaky Debian/Ubuntu ARM64 job: - Emulator level: pin a modern QEMU (tonistiigi/binfmt qemu-v9.2.2), which fixes rseq emulation (QEMU >= 7.2). - Guest level: disable rseq on the Debian container via GLIBC_TUNABLES=glibc.pthread.rseq=0. No retryCountOnTaskFailure, no skipped tests. RHEL9 ARM64 and Alpine legs are untouched. AB#47276
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Jahnvi Thakkar (jahnvi480)
August 14, 2026 10:08
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Pull request overview
This PR updates the ARM64 Linux PR-validation CI job to eliminate intermittent Debian ARM64 segfaults under QEMU user-mode emulation by switching to a newer pinned QEMU binfmt image and disabling glibc rseq inside the Debian container.
Changes:
- Replace
multiarch/qemu-user-staticwith pinnedtonistiigi/binfmt:qemu-v9.2.2for ARM64 emulation. - Add Debian-only
GLIBC_TUNABLES=glibc.pthread.rseq=0during ARM64 test container creation to disable rseq.
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Address PR review: bare `--install arm64` is a no-op when the hosted agent already has an arm64 handler registered (kernel returns EEXIST and tonistiigi/binfmt leaves the existing, possibly older QEMU in place, logging but not failing). That could silently keep the old buggy QEMU on the Ubuntu_ARM64 leg, which has no guest-side GLIBC_TUNABLES guard. tonistiigi/binfmt has no `--reset` flag (that was multiarch/qemu-user- static); the equivalent is `--uninstall arm64 --install arm64` (uninstall runs before install in run()). `--uninstall arm64` resolves through the arch config to the qemu-aarch64 handler via the -aarch64 suffix match and is a harmless no-op when nothing is registered. Also reword the container-creation comment to clarify that only the GLIBC_TUNABLES/rseq-disable guard is Debian-scoped; the ARM64 emulation is shared by both matrix legs. AB#47276
Drop the emulator-side QEMU swap (pinned tonistiigi/binfmt + uninstall/install) and revert the buildx step to the original multiarch/qemu-user-static registration. The crash mechanism is glibc rseq; disabling it in the guest via GLIBC_TUNABLES=glibc.pthread.rseq=0 neutralizes the root cause deterministically, without depending on binfmt registration order or agent pre-registration state. Apply the guard unconditionally to both ARM64 matrix legs (Debian 12 / glibc 2.36 and Ubuntu 22.04 / glibc 2.35) -- both share the same emulated-arm64 path and both glibc versions ship rseq -- which also removes the Ubuntu-leg exposure that motivated the emulator swap. Net change vs main is now a single env var; no new image dependency. AB#47276
…fault The Debian ARM64 leg SIGSEGVs (exit 139) during the apt 'Setting up python3' post-install byte-compilation under QEMU user-mode emulation (proven by build 167144, which ran the prior guest-side GLIBC_TUNABLES=glibc.pthread.rseq=0 guard and still crashed). Disabling rseq does not fix this emulator-level bug. Instead, avoid the crashing operation entirely: run the Debian leg on the python:3.11-bookworm image (Debian 12 + Python 3.11 already installed and byte-compiled natively at image-build time) and stop apt-installing the python3* packages. Python (pip, venv, dev headers) comes from /usr/local, pybind11 is installed via pip from requirements.txt, and only non-Python build tools (cmake, curl, wget, gnupg, build-essential) are pulled from apt -- none of which depend on the Debian python3 package. The ineffective rseq guard is removed. AB#47276
Jahnvi Thakkar (jahnvi480)
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📊 Code Coverage Report
Diff CoverageDiff: main...HEAD, staged and unstaged changesNo lines with coverage information in this diff. 📋 Files Needing Attention📉 Files with overall lowest coverage (click to expand)mssql_python.pybind.logger_bridge.cpp: 59.2%
mssql_python.pybind.ddbc_bindings.h: 59.9%
mssql_python.pybind.logger_bridge.hpp: 70.8%
mssql_python.pybind.ddbc_bindings.cpp: 76.6%
mssql_python.__init__.py: 77.6%
mssql_python.row.py: 77.6%
mssql_python.ddbc_bindings.py: 79.6%
mssql_python.pybind.connection.connection_pool.cpp: 81.4%
mssql_python.pybind.connection.connection.cpp: 84.3%
mssql_python.logging.py: 85.5%🔗 Quick Links
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Summary
The Debian ARM64 leg of the PR validation pipeline SIGSEGVs (exit 139) during
the apt
Setting up python3post-install byte-compilation under QEMU user-modeemulation on the x86_64 hosted agent. This is an emulator-level crash in the
Debian
python3package's post-install script, not something the guest cansuppress: build 167144 ran a
GLIBC_TUNABLES=glibc.pthread.rseq=0guard andstill crashed at exactly the same point, disproving the earlier rseq theory.
This change avoids the crashing operation entirely instead of trying to make
QEMU emulate it correctly:
python:3.11-bookworm(Debian 12 + CPython3.11 already installed and byte-compiled natively at image-build time)
instead of
debian:12.python3*packages (the trigger). Python — with pip, venv and dev headers —comes from
/usr/local;pybind11comes from pip (already inrequirements.txt); CMake auto-detects both from the active interpreter, sothe apt
python3-dev/pybind11-devpackages are redundant. Only non-Pythonbuild tools (
cmake curl wget gnupg build-essential) are apt-installed, noneof which depend on the Debian
python3package.software-properties-commonwas unused (the ODBC repo is added via
curl+dpkg -i, notadd-apt-repository).GLIBC_TUNABLESrseq guard is removed.The Ubuntu ARM64 leg is unchanged (it does not crash). Pytest subprocess
segfaults under QEMU are a separate concern and will be
skipif-guarded.AB#47276