Charles-François Natali added the comment:
> Did you forget to attach the patch?
Oops...
----------
Added file: http://bugs.python.org/file29295/tstate_after_fork.diff
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue17094>
_______________________________________
diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -728,6 +728,31 @@
for t in threads:
t.join()
+ @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()")
+ def test_clear_threads_states_after_fork(self):
+ # Issue #17094: check that threads states are cleared after fork()
+
+ # start a bunch of threads
+ threads = []
+ for i in range(16):
+ t = threading.Thread(target=lambda : time.sleep(0.3))
+ threads.append(t)
+ t.start()
+
+ pid = os.fork()
+ if pid == 0:
+ # check that threads states have been cleared
+ if len(sys._current_frames()) == 1:
+ os._exit(0)
+ else:
+ os._exit(1)
+ else:
+ _, status = os.waitpid(pid, 0)
+ self.assertEqual(0, status)
+
+ for t in threads:
+ t.join()
+
class ThreadingExceptionTests(BaseTestCase):
# A RuntimeError should be raised if Thread.start() is called
diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -364,29 +364,29 @@
drop_gil(tstate);
}
-/* This function is called from PyOS_AfterFork to ensure that newly
- created child processes don't hold locks referring to threads which
- are not running in the child process. (This could also be done using
- pthread_atfork mechanism, at least for the pthreads implementation.) */
+/* This function is called from PyOS_AfterFork to destroy all threads which are
+ * not running in the child process, and clear internal locks which might be
+ * held by those threads. (This could also be done using pthread_atfork
+ * mechanism, at least for the pthreads implementation.) */
void
PyEval_ReInitThreads(void)
{
_Py_IDENTIFIER(_after_fork);
PyObject *threading, *result;
- PyThreadState *tstate = PyThreadState_GET();
+ PyThreadState *current_tstate = PyThreadState_GET();
+ PyThreadState *tstate, *tstate_next;
if (!gil_created())
return;
recreate_gil();
pending_lock = PyThread_allocate_lock();
- take_gil(tstate);
+ take_gil(current_tstate);
main_thread = PyThread_get_thread_ident();
/* Update the threading module with the new state.
*/
- tstate = PyThreadState_GET();
- threading = PyMapping_GetItemString(tstate->interp->modules,
+ threading = PyMapping_GetItemString(current_tstate->interp->modules,
"threading");
if (threading == NULL) {
/* threading not imported */
@@ -399,6 +399,16 @@
else
Py_DECREF(result);
Py_DECREF(threading);
+
+ /* destroy all threads except the current one */
+ for (tstate = PyInterpreterState_ThreadHead(current_tstate->interp);
+ tstate; tstate = tstate_next) {
+ tstate_next = PyThreadState_Next(tstate);
+ if (tstate != current_tstate) {
+ PyThreadState_Clear(tstate);
+ PyThreadState_Delete(tstate);
+ }
+ }
}
#else
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