A ripgrep crash investigation ends up finding a kernel TLB-shootdown race
BenBajarin · x · 2026-07-28
A ripgrep segfault investigation ends up exposing a kernel race
The linked GitHub repo documents an unusually deep debugging session around ripgrep #3494. What looked like a user-space crash turned out to be a kernel TLB-shootdown race that made a thread’s own write disappear a few instructions later.
- The analysis starts from a reproducible SIGSEGV seen in musl mallocng during large multi-threaded searches.
- Instrumentation showed the crash mechanism was not an ordinary allocator bug: the page backing a freshly faulted anonymous page was being replaced mid-function.
- The poster also jokes that tools and models helped investigate the bug instead of blocking on safety concerns.
This is both a neat systems debugging story and a good example of AI-assisted low-level investigation.
Related event: US AI Blocked by Safety, Chinese AI Finds Kernel Bug(4 posts)→
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