OpenAI Fixes 18-Year-Old GNU libunwind Bug by Treating Crash Debugging Like Epidemiology

OpenAI engineers discovered two unrelated bugs in Rockset, their C++ data infrastructure powering ChatGPT, by applying 'epidemiological debugging' — building a pipeline to analyze every production core dump from the past year at a population level rather than inspecting individual crashes. This revealed a silent hardware CPU corruption on a single Azure host and an 18-year-old race condition in GNU libunwind's _Ux86_64_setcontext function. The libunwind bug involves a one-instruction-wide window where the stack pointer is updated before the instruction pointer is read, allowing a signal to corrupt the struct. OpenAI's heavy use of timer-based SIGUSR2 signals made this theoretical race a real production crash. The fix — reordering instructions so %rip is read before %rsp is updated — was upstreamed to GNU libunwind. The key lesson: building complete, labeled population data across all failures reveals structure that individual case analysis cannot.

Nguồn: https://www.infoq.com/news/2026/07/openai-libunwind-core-dumps. 8sync News chỉ tóm tắt và dẫn link; bản quyền nội dung thuộc tác giả và nguồn gốc.