When compiling Qt 5.15.2 from the official open source sources, we encountered a problem in combination with our build server: The build process was interrupted while compiling the Chromium-based “WebEngine” component with initially mysterious error messages. A look at the kernel log using dmesg -w then quickly revealed that the so-called OOM killer of the Linux kernel had struck. Apparently the RAM consumption of the build process was so memory-intensive that the process had to be aborted to keep the operating system running.