What Is the OOM Killer?
The OOM killer is the part of the Linux kernel that, when memory is exhausted and no other recourse exists, selects and kills a process to free memory. It scores candidate processes by their memory footprint and other heuristics to choose a victim. The killed process simply disappears, often with little warning in its own logs.
Why it matters
On Latchkey runners and other CI machines, a build that exceeds available memory is frequently ended by the OOM killer, showing up as an abrupt, unexplained kill. Checking the kernel log for OOM events is the way to confirm memory, not the code, caused the failure.
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