Out of memory in systemd-journald on CentOS 7 caused by file‑descriptor leak

Goal

Determine whether enabling CONFIG_DEBUG_KMEMLEAK by default in the CentOS 7 kernel would provide automated detection of similar leaks without imposing an unacceptable performance penalty.

Constraints and uncertainty

The journald file‑descriptor leak was fixed in systemd-219-62.el7_8.2, yet the kernel still ships with CONFIG_DEBUG_KMEMLEAK disabled. Enabling the option adds kernel memory overhead and CPU usage, which may affect production workloads. Both the userspace patch and a kernel update are required to fully eliminate the leak, and the impact of kmemleak on typical workloads has not been quantified in the CentOS release notes.

Open questions

1. What is the measured performance impact of enabling CONFIG_DEBUG_KMEMLEAK on representative production workloads?
2. Are there any known regressions or side effects when kmemleak is active together with the patched systemd package?
3. Should the CentOS kernel maintainers change the default configuration to enable kmemleak, and what criteria would trigger that decision?