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xcat-dep/lib
Daniel Hilst b435ae4bad fix(xcat-dep): an emulated build that deadlocks hangs the pipeline forever
Every per-package build ran through a bare system() call with no wall-clock
bound. Under qemu-user a build can deadlock -- a riscv64 goconserver `go build`
held both Go pids in futex_wait for 26 minutes with no CPU ticks and no open
socket -- and the step then never returns. The pipeline does not go red; it
stops, and a stopped run reads as "still running".

XCAT::BuildUtils::run_bounded runs the command in its own process group, kills
that group when a budget expires, and prints first what the manual
investigation had to collect by hand: the process tree, each pid's kernel wchan
and stack, its open socket count, and the CPU ticks the group used across a
20-second sample. Zero ticks names a deadlock; ticks name a build that is only
slow. BuildUtils::build_deb_in_chroot bounds every Ubuntu package build, and
mockbuild-all.pl bounds the dep and perl steps of a forcearch target.

The budget is 900 seconds for a native build and ten times that for a foreign
architecture, because qemu-user under TCG runs at roughly a tenth of native
speed. Both sit about five times above the slowest build measured on
xcat-master-ub: 3 minutes native, and 26 minutes for riscv64 ipmitool-xcat on
resolute with four codenames building at once. Native mock steps stay unbounded
-- no measurement of them exists, and a guessed budget would turn a trusted
cell red. sbuild-all.pl --build-timeout and mockbuild-all.pl --build-timeout
override the default; 0 removes the bound.

t/build_timeout.t fails without this change: run_bounded never returns and the
test reports the hang instead of blocking.

Signed-off-by: Daniel Hilst <392820+dhilst@users.noreply.github.com>
2026-09-06 00:24:11 -03:00
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