https://github.com/python/cpython/commit/01157e0cdff1321a065b0a00c5a97460f52af07e commit: 01157e0cdff1321a065b0a00c5a97460f52af07e branch: main author: Petr Viktorin <[email protected]> committer: encukou <[email protected]> date: 2025-09-30T16:43:49+02:00 summary:
gh-139116: tracemalloc: Detach thread state when acquiring tables_lock (GH-139449) * gh-139116: tracemalloc: Detach thread state when acquiring tables_lock This prevents a deadlock when: - One thread is in `_PyTraceMalloc_Stop`, with `TABLES_LOCK` held, calling `PyRefTracer_SetTracer` which wants to stop the world - Another is thread in `PyTraceMalloc_Track`, just attached thread state, waiting for `TABLES_LOCK` Detaching the thread state while waiting for `TABLES_LOCK` allows `PyRefTracer_SetTracer` to stop the world. Co-authored-by: Peter Bierma <[email protected]> files: A Misc/NEWS.d/next/Core_and_Builtins/2025-09-30-14-57-19.gh-issue-139116.nlVf40.rst M Python/tracemalloc.c diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-09-30-14-57-19.gh-issue-139116.nlVf40.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-09-30-14-57-19.gh-issue-139116.nlVf40.rst new file mode 100644 index 00000000000000..00692e97c44fb5 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-09-30-14-57-19.gh-issue-139116.nlVf40.rst @@ -0,0 +1,2 @@ +Prevent a deadlock when multiple threads start, stop and use :mod:`tracemalloc` +simultaneously. diff --git a/Python/tracemalloc.c b/Python/tracemalloc.c index 7066a214f1065b..7a0853b6a07f55 100644 --- a/Python/tracemalloc.c +++ b/Python/tracemalloc.c @@ -36,7 +36,7 @@ static int _PyTraceMalloc_TraceRef(PyObject *op, PyRefTracerEvent event, the GIL held from PyMem_RawFree(). It cannot acquire the lock because it would introduce a deadlock in _PyThreadState_DeleteCurrent(). */ #define tables_lock _PyRuntime.tracemalloc.tables_lock -#define TABLES_LOCK() PyMutex_LockFlags(&tables_lock, _Py_LOCK_DONT_DETACH) +#define TABLES_LOCK() PyMutex_Lock(&tables_lock) #define TABLES_UNLOCK() PyMutex_Unlock(&tables_lock) _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
