From 72262f46e72437a8e299a7a51fa41298ed3133b0 Mon Sep 17 00:00:00 2001 From: Kumar Aditya Date: Tue, 22 Jul 2025 02:05:25 +0530 Subject: [PATCH] gh-136870: fix data race in `PyThreadState_Clear` on `sys_tracing_threads` (GH-136951) In free-threading, multiple threads can be cleared concurrently as such the modifications on `sys_tracing_threads` should be done while holding the profile lock, otherwise it can race with other threads setting up profiling. (cherry picked from commit f183996eb77fd2d5662c62667298c292c943ebf5) Co-authored-by: Kumar Aditya --- Python/pystate.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Python/pystate.c b/Python/pystate.c index 015e9f8725c1af..aa2c4bd51814c3 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -1793,6 +1793,10 @@ PyThreadState_Clear(PyThreadState *tstate) "PyThreadState_Clear: warning: thread still has a generator\n"); } +#ifdef Py_GIL_DISABLED + PyMutex_Lock(&_PyRuntime.ceval.sys_trace_profile_mutex); +#endif + if (tstate->c_profilefunc != NULL) { tstate->interp->sys_profiling_threads--; tstate->c_profilefunc = NULL; @@ -1801,6 +1805,11 @@ PyThreadState_Clear(PyThreadState *tstate) tstate->interp->sys_tracing_threads--; tstate->c_tracefunc = NULL; } + +#ifdef Py_GIL_DISABLED + PyMutex_Unlock(&_PyRuntime.ceval.sys_trace_profile_mutex); +#endif + Py_CLEAR(tstate->c_profileobj); Py_CLEAR(tstate->c_traceobj);