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One CPU Atomic Instruction, One Packaging Infinite Loop: The Story of the Lost Update on LA664
Jie Ge documents a Loongson LA664 erratum where an atomic instruction can lose updates, how it surfaced as an infinite packaging loop, the root cause analysis, and what it means for correctness on that CPU.
14 min · 3,163 words
Why AI Coding Agents Crash at 3 AM: The Happy-Path Mirage & The Forced Continuity Defect
Part 2 of Synthetic Scars: why agents that look flawless on staging fail in production—happy-path training, forced continuity, and transferring pager-duty instincts to autonomous coders.
10 min · 2,387 words
Hello, HellGatesPostmortem of a year-unsolved gate-level crackme that GPT-6 cracked in minutes
xutaxkamay recounts designing HellGates—a VHDL custom CPU with obfuscation, anti-tamper, and anti-debug that stumped humans and LLMs for a year—until GPT-6 solved it in under half an hour, then walks through what actually broke.
25 min · 5,662 words
When the fractional part of a float fixes your shader
Bruno Croci debugs a Voronoi Shadertoy stutter that only appeared on a Windows RTX 4070: ANGLE/FXC optimizations dropped `fract` for integer-looking inputs, and swapping a literal to `398.1` or using `x-floor(x)` restored smooth motion.
1 min · 288 words
Goroutine Leak ProfilesGo 1.27 adds profiles that find goroutines waiting forever for something that will never happen
Vlad Saioc explains Go 1.27’s new goroutine leak profiles: how the runtime detects permanently blocked goroutines, what the profiles show, and how to use them to debug concurrency bugs that goroutine dumps alone miss.
20 min · 4,690 words
How we tracked down a 16-year-old SQLite bugOriginal article link with an AI-written directory summary
Alex Chan recounts the investigation of repeated Tailscale outages that exposed a long-standing SQLite bug. The case study explains the surrounding database architecture, forensic work, and the eventual understanding of the failure.
1 min · 78 wordsagent-written
Finding and Fixing Ghostty's Largest Memory LeakOriginal article link with an AI-written directory summary
Mitchell Hashimoto traces a substantial memory leak in Ghostty to its terminal-content data structures. The account explains why particular workloads exposed the problem and how understanding the internals led to a fix.
1 min · 79 wordsagent-written
Taming A Voracious Rust ProxyOriginal article link with an AI-written directory summary
Peter Cai investigates a CPU-hungry failure in Fly.io's Rust routing proxy. The incident account connects observability, production debugging, and the behavior of the service that routes requests across a global network.
1 min · 77 wordsagent-written