--- title: "Tracing a memory leak bug in PID 1 and contributing an upstream fix: a Linux support story" url: https://daily.dev/posts/tracing-a-memory-leak-bug-in-pid-1-and-contributing-an-upstream-fix-a-linux-support-story-acqq4ixcg source_url: https://ubuntu.com/blog/fixing-memory-bug type: article source: "Ubuntu" published: 2026-07-17T13:27:23.065Z updated: 2026-07-18T06:21:05.851Z tags: ["linux"] reading_time: 6 upvotes: 2 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Tracing a memory leak bug in PID 1 and contributing an upstream fix: a Linux support story **[Ubuntu](https://daily.dev/sources/ubuntu)** · 6 min read · 2 upvotes · 0 comments ## Summary A global retail company's Ceph cluster nodes were experiencing out-of-memory kills, with PID 1 (systemd) consuming ~70 GB of RAM instead of the expected 8 GB. Canonical Support engineers traced the root cause across three system layers: a cephadm orchestration misconfiguration was repeatedly attempting to 'zap' a non-existent OSD, causing a ceph-volume Docker container to spin up and tear down in a continuous loop. This generated millions of mount table entries, triggering a kernel race condition that caused systemd to continuously reparse the mount table while glibc's allocator retained the memory without returning it to the kernel. The fix involved correcting the cephadm loop as a workaround, then isolating a minimal reproducer (mounting/unmounting tmpfs in a tight loop) to characterize the kernel race condition precisely. A patch was merged into the mainline Linux kernel and subsequently landed in several Ubuntu kernel releases via the Stable Release Update process. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Mount Mayhem at Netflix: Scaling Containers on Modern CPUs](https://daily.dev/posts/mount-mayhem-at-netflix-scaling-containers-on-modern-cpus-ckvvan6ve) · Netflix TechBlog · 50 upvotes · 1 comments - [Pinterest Engineers Eliminate CPU Zombies to Resolve Production Bottlenecks](https://daily.dev/posts/pinterest-engineers-eliminate-cpu-zombies-to-resolve-production-bottlenecks-av8vpr9bo) · InfoQ · 4 upvotes · 0 comments - [Netflix Uncovers Kernel-Level Bottlenecks While Scaling Containers on Modern CPUs](https://daily.dev/posts/netflix-uncovers-kernel-level-bottlenecks-while-scaling-containers-on-modern-cpus-bfs33g6uj) · InfoQ · 3 upvotes · 0 comments - [Linux Addressing Out-Of-Memory Killer Inaccuracy On Large Core Count Systems](https://daily.dev/posts/linux-addressing-out-of-memory-killer-inaccuracy-on-large-core-count-systems-f5fuemf2q) · Phoronix · 0 upvotes · 0 comments - [Linux 7.2-rc7 Addresses A "Nasty" Race Condition Leading To Use-After-Free After 8 Years](https://daily.dev/posts/linux-7-2-rc7-addresses-a-nasty-race-condition-leading-to-use-after-free-after-8-years-xkxkoetzs) · Phoronix · 0 upvotes · 0 comments --- Tags: [#linux](https://daily.dev/tags/linux) [View this post on daily.dev](https://daily.dev/posts/tracing-a-memory-leak-bug-in-pid-1-and-contributing-an-upstream-fix-a-linux-support-story-acqq4ixcg)