python · izbyshev · Jan 18, 2021 · Jan 21, 2021
diff --git a/Misc/NEWS.d/next/Library/2021-01-21-18-03-09.bpo-42888.0oAR2x.rst b/Misc/NEWS.d/next/Library/2021-01-21-18-03-09.bpo-42888.0oAR2x.rst
@@ -0,0 +1,4 @@
+Remove calls of :c:func:`PyThread_exit_thread()` from top-level thread
+functions, thereby avoiding a runtime dependency on ``libgcc_s.so`` and
+associated issues with lazy-loading it via ``dlopen()`` in typical scenarios
+on glibc-based Linux systems.
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
@@ -4512,8 +4512,6 @@ temporary_c_thread(void *data)
    PyGILState_Release(state);

    PyThread_release_lock(test_c_thread->exit_event);
-
-    PyThread_exit_thread();
 }

 static PyObject *

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
@@ -1087,8 +1087,6 @@ thread_run(void *boot_raw)
    tstate->interp->num_threads--;
    PyThreadState_Clear(tstate);
    _PyThreadState_DeleteCurrent(tstate);
-
-    PyThread_exit_thread();
 }

 static PyObject *

diff --git a/Programs/_testembed.c b/Programs/_testembed.c
@@ -241,8 +241,6 @@ static void bpo20891_thread(void *lockp)
    PyGILState_Release(state);

    PyThread_release_lock(lock);
-
-    PyThread_exit_thread();
 }

 static int test_bpo20891(void)

diff --git a/Python/thread_nt.h b/Python/thread_nt.h
@@ -160,6 +160,13 @@ PyThread__init_thread(void)
 * Thread support.
 */

+static void
+_pythread_at_thread_exit(void)
+{
+    dprintf(("%lu: _pythread_at_thread_exit called\n",
+            PyThread_get_thread_ident()));
+}
+
 typedef struct {
    void (*func)(void*);
    void *arg;
@@ -175,6 +182,7 @@ bootstrap(void *call)
    void *arg = obj->arg;
    HeapFree(GetProcessHeap(), 0, obj);
    func(arg);
+    _pythread_at_thread_exit();
    return 0;
 }

@@ -254,7 +262,7 @@ PyThread_get_thread_native_id(void)
 void _Py_NO_RETURN
 PyThread_exit_thread(void)
 {
-    dprintf(("%lu: PyThread_exit_thread called\n", PyThread_get_thread_ident()));
+    _pythread_at_thread_exit();
    if (!initialized)
        exit(0);
    _endthreadex(0);

diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
@@ -218,6 +218,12 @@ PyThread__init_thread(void)
 * Thread support.
 */

+static void
+_pythread_at_thread_exit(void)
+{
+    dprintf(("_pythread_at_thread_exit called\n"));
+}
+
 /* bpo-33015: pythread_callback struct and pythread_wrapper() cast
   "void func(void *)" to "void* func(void *)": always return NULL.

@@ -238,6 +244,7 @@ pythread_wrapper(void *arg)
    PyMem_RawFree(arg);

    func(func_arg);
+    _pythread_at_thread_exit();
    return NULL;
 }

@@ -359,7 +366,7 @@ PyThread_get_thread_native_id(void)
 void _Py_NO_RETURN
 PyThread_exit_thread(void)
 {
-    dprintf(("PyThread_exit_thread called\n"));
+    _pythread_at_thread_exit();
    if (!initialized)
        exit(0);
    pthread_exit(0);