It doesn't make sense for the reader to spend more energy than the writer spent on creating it.
Headline: The crash is real and reproducible.
https://github.com/dfoxfranke/ripgrep-3494-analysis#6-cross-...
produced (machine from original report)
not reproduced
not reproduced
not reproduced
not reproduced
You got none of that here. It’s just realms of text.
That's the trillion-dollar catch, isn't it. LLMs love to write 30 paragraphs about some plausibly-correct-sounding explanation that is just as likely to be completely fucking wrong as it is accurate. The bug might be real, but that doesn't mean this analysis is accurate, and trying to figure out where the LLM went off the rails can be a nightmare. If you can actually understand the bug, it doesn't take 30 paragraphs to explain it. I would throw this bug report into my junk bin if I were on the receiving end of it, and I say that as someone who will spend days troubleshooting any issue a user will help me diagnose even if it only happens on their machine.
This sounds to me like either (a) a complex race involving a CPU migration at an awkward time or (b) a bug in the zap path transiently exposing wrong PTEs.
Also, I don’t think the zero page has pfn zero.
If I had to throw a dart, I would guess that direct page table zapping is allowing a CPU to read through a higher-level-paging-structure cached entry to a table that has been freed and reused. Yuck. I’ve debugged one of these before.
I think the broad strokes are that, due to bad locking in the kernel, mmap() returns a VA that a concurrent munmap() is still in the middle of unmapping. The specifics beyond that seem murky/speculative/inconsistent.
Alternatively, it could even be a hardware bug!
The overflow would still overflow; the use-after-free would still use after free; a musl mask race would still race.
Great way to summarize cultural "economics"
Couldn't put the words on this pattern but sometimes all I care about is that someone cared about.
wild_pointer•1h ago