[3.11]pythonGH-112275: Fix HEAD_LOCK deadlock in child process after …

…fork (python#112336) HEAD_LOCK is called from _PyEval_ReInitThreads->_PyThreadState_DeleteExcept before _PyRuntimeState_ReInitThreads reinit runtime->interpreters.mutex which might be locked before fork. Co-authored-by: Łukasz Langa <lukasz@langa.pl>
ambv · Sep 4, 2024 · 522799a · 522799a
1 parent 851821d
commit 522799a
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-09-04-18-20-11.gh-issue-112275.W_iMiB.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-04-18-20-11.gh-issue-112275.W_iMiB.rst
@@ -0,0 +1,3 @@
+A deadlock involving ``pystate.c``'s ``HEAD_LOCK`` in ``posixmodule.c``
+at fork is now fixed. Patch by ChuBoning based on previous Python 3.12
+fix by Victor Stinner.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -603,6 +603,11 @@ PyOS_AfterFork_Child(void)
  goto fatal_error;
  }
 
+ status = _PyRuntimeState_ReInitThreads(runtime);
+ if (_PyStatus_EXCEPTION(status)) {
+ goto fatal_error;
+ }
+
  PyThreadState *tstate = _PyThreadState_GET();
  _Py_EnsureTstateNotNULL(tstate);
 
@@ -622,11 +627,6 @@ PyOS_AfterFork_Child(void)
 
  _PySignal_AfterFork();
 
- status = _PyRuntimeState_ReInitThreads(runtime);
- if (_PyStatus_EXCEPTION(status)) {
- goto fatal_error;
- }
-
  status = _PyInterpreterState_DeleteExceptMain(runtime);
  if (_PyStatus_EXCEPTION(status)) {
  goto fatal_error;