Summary:
InjectedErrorLog is a lock-free circular ring buffer designed to be safe to call from signal handlers (which cannot use locks). It has an intentional benign data race between Record() (called by worker threads) and PrintAll() (called by the main thread from a signal/termination handler). The code documents this trade-off in comments, but was missing TSAN suppression annotations.
Simply adding TSAN_SUPPRESSION (__attribute__((no_sanitize("thread")))) is insufficient because TSAN still intercepts libc functions like vsnprintf/snprintf -- accesses through these interceptors are still tracked even when the calling function is annotated.
The fix:
1. Add TSAN_SUPPRESSION to both Record() and PrintAll() to suppress direct field reads/writes in the function body.
2. Restructure both functions to use local stack buffers for vsnprintf/snprintf operations instead of operating directly on shared entry data. This avoids passing shared memory through TSAN-intercepted libc functions.
Also adds fault_injection_fs_test with a ConcurrentRecordAndPrintAll test that exercises the concurrent Record() + PrintAll() pattern and verifies no TSAN race is reported.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/14467
Test Plan:
- fault_injection_fs_test passes under TSAN (buck2 test fbcode//mode/dbg-tsan)
- Reverted fix, re-ran: Fatal (6 TSAN warnings) -- round-trip confirmed
- fault_injection_fs_test passes under debug mode (no regression)
Reviewed By: mszeszko-meta
Differential Revision: D96948483
Pulled By: xingbowang
fbshipit-source-id: efdd5eafa12a5a82f973e40aa327901cc5f95033
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