fix: use shared_ptr in ThreadedAsyncOperation to prevent SIGBUS on macOS#21625
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fix: use shared_ptr in ThreadedAsyncOperation to prevent SIGBUS on macOS#21625
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TSFN BlockingCall (napi_tsfn_blocking) only blocks on queue insertion, NOT on callback completion. The callback runs asynchronously on the JS thread, so `delete this` on the worker thread raced with the callback reading member fields — confirmed via ASAN. Fix: manage ThreadedAsyncOperation via shared_ptr (enable_shared_from_this). Both the worker thread lambda and the TSFN callback capture a shared_ptr, so the object lives until both are done. Verified clean under ASAN with 1000 concurrent operations.
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Reverts #21138 on v4. ThreadedAsyncOperation has a use-after-free that causes SIGBUS on macOS and silent memory corruption on Linux. Restoring AsyncOperation (libuv pool) with the original deadlock-prevention semaphore (UV_THREADPOOL_SIZE / 2) until a proper fix lands on next (#21625). [Post mortem](https://gist.github.com/ludamad/443afe321853389a08693c4ff73676f7)
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Fixes use-after-free in
ThreadedAsyncOperation(#21138) that causes SIGBUS on macOS and silent memory corruption on Linux. v4 is handled by reverting: #21630.Root cause: TSFN
BlockingCall(napi_tsfn_blocking) only blocks on queue insertion, NOT on callback completion. The callback runs asynchronously on the JS main thread, sodelete thison the worker thread raced with the callback reading member fields. macOS's magazine malloc aggressively unmaps freed pages, turning this into a consistent SIGBUS. Linux glibc keeps pages mapped, so the race is silent.Fix: manage
ThreadedAsyncOperationviashared_ptr(enable_shared_from_this). Both the worker thread lambda and the TSFN callback capture ashared_ptr, so the object lives until both are done. Verified clean under ASAN with 1000+ concurrent operations (heap-use-after-free confirmed on buggy code, clean on fix).Full post mortem