mirror of
https://github.com/kuhyx/testsAndMisc.git
synced 2026-11-11 16:34:06 +01:00
Krzysztof Rudnicki
8e24ff093f
On 2026-07-30 a kernel upgrade left the machine in systemd emergency mode on three consecutive boots. The upgrade replaced /usr/lib/modules/<old> with <new>, but the new kernel never reached the ESP, so the firmware kept booting the OLD vmlinuz whose module tree had just been deleted. Nothing modular could load after pivot-root — including vfat, which meant /boot itself could not be mounted, local-fs.target failed, and systemd dropped to an emergency shell. pacman reported the transaction as successful. Root cause: pacman-git with ParallelDownloads > 1 segfaults every forked alpm hook child, silently skipping 90-mkinitcpio-install and depmod. boot-repair is self-contained (no repo libs — it must run in the emergency shell) and fully offline (missing modules are recovered from /var/cache/pacman/pkg). It repairs by default; --dry-run inspects. It detects and fixes: read-only root, noauto/nofail fstab drift, orphaned kernel files shadowing an unmounted ESP, unloadable vfat, unmounted ESP, missing modules.dep, ESP kernel != installed tree, stale initramfs, and ParallelDownloads > 1. Two pacman hooks make the failure impossible rather than merely recoverable: 05-boot-mounted-guard aborts a kernel transaction when the ESP is unmounted (AbortOnFail), and 99-boot-autorepair fixes ESP drift after the transaction, before the machine is ever rebooted. Safety: a module tree counts as usable only if it has BOTH vmlinuz and kernel/, so the metadata-only wreckage this bug leaves — which sorts newer — is never chosen as the target. Files under /boot are deleted only while it is not a mountpoint AND contains no EFI/ or loader/; deleting after mounting would destroy the real kernel. Verified: - 31/31 fixture tests (--root against throwaway trees, no privileges) - 11/11 reversible live tests on the real machine: unmounted the real ESP, planted shadow files, confirmed they were deleted and the ESP then mounted with EFI/, loader/ and kernel 7.1.5-arch1-2 intact - Gate proven against a real transaction with the ESP unmounted: "failed to commit transaction", no packages upgraded, nothing written - shellcheck + shfmt clean, pre-commit passing Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
23 lines
842 B
Plaintext
23 lines
842 B
Plaintext
# After a kernel transaction, verify the ESP actually received the new kernel
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# and repair it if it did not.
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#
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# This is auto-recovery rather than a warning: if mkinitcpio's own hook was
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# skipped (the ParallelDownloads segfault bug), this puts the kernel and
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# initramfs on the ESP before the machine is ever rebooted. If it cannot, it
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# exits non-zero so the transaction ends loudly instead of silently succeeding.
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#
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# Note: this hook is itself forked by alpm, so it is subject to the same
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# segfault bug it compensates for. That is why boot-repair also enforces
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# ParallelDownloads = 1 — belt and braces.
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[Trigger]
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Type = Path
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Operation = Install
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Operation = Upgrade
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Target = usr/lib/modules/*/vmlinuz
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[Action]
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Description = Verifying the ESP received the new kernel...
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When = PostTransaction
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Exec = /usr/local/sbin/boot-repair --auto
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