Unbounded memory usage by TCP for receive buffers, and how we fixed it

What this post added

This post details a specific, critical issue discovered in the Linux kernel's TCP receive buffer memory management. It explains how certain conditions can lead to unbounded memory allocation, impacting overall server performance and causing packet loss. The post outlines the root cause, provides a reproducible lab setup, and discusses the implications for Cloudflare's production network, highlighting the need for kernel-level fixes to maintain optimal performance and stability.