[3.13] gh-137400: Fix thread-safety issues when profiling all threads (gh-137518) (gh-137733)

There were a few thread-safety issues when profiling or tracing all
threads via PyEval_SetProfileAllThreads or PyEval_SetTraceAllThreads:

* The loop over thread states could crash if a thread exits concurrently
  (in both the free threading and default build)
* The modification of `c_profilefunc` and `c_tracefunc` wasn't
  thread-safe on the free threading build.
(cherry picked from commit a10152f8fd)
This commit is contained in:
Sam Gross 2025-10-09 11:42:47 -04:00 committed by GitHub
parent f6186a3709
commit 16d2e97cf3
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
12 changed files with 29814 additions and 29714 deletions

View file

@ -148,7 +148,15 @@ dummy_func(
tier1 inst(RESUME, (--)) {
assert(frame == tstate->current_frame);
if (tstate->tracing == 0) {
#ifdef Py_GIL_DISABLED
// For thread-safety, we need to check instrumentation version
// even when tracing. Otherwise, another thread may concurrently
// re-write the bytecode while we are executing this function.
int check_instrumentation = 1;
#else
int check_instrumentation = (tstate->tracing == 0);
#endif
if (check_instrumentation) {
uintptr_t global_version =
_Py_atomic_load_uintptr_relaxed(&tstate->eval_breaker) &
~_PY_EVAL_EVENTS_MASK;