Exit Code 137 in CI: OOM-Killed (SIGKILL) and How to Fix It

Exit code 137 means SIGKILL (128 + 9) terminated the process - on memory-limited runners this is overwhelmingly the OOM killer.

When a step exits 137, the kernel forcibly killed it. The most common cause in CI is the cgroup out-of-memory killer reclaiming memory under pressure.

What it means

SIGKILL cannot be caught or ignored. 137 = 128 + 9. On CI runners the killer is usually the OOM killer; it can also be docker stop past its grace period or a kill -9.

Common causes

The job exceeded the runner or container memory limit.
A build (webpack, tsc, gradle) or test suite spiked peak RSS.
A Docker container hit its --memory cap.

How to fix it

Give the job more memory or lower peak usage (reduce parallelism, cap heap sizes). This is a mechanical, transient failure class: self-healing managed runners like Latchkey detect an OOM-kill and automatically retry the job with the right resources.

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