gh-90549: Fix leak of global named resources using multiprocessing spawn (#30617)

Co-authored-by: XD Trol <milestonejxd@gmail.com>
Co-authored-by: Antoine Pitrou <pitrou@free.fr>

2 files changed, 22 insertions, 2 deletions

diff --git a/Lib/multiprocessing/context.py b/Lib/multiprocessing/context.py
index 8d0525d..b1960ea 100644
--- a/Lib/multiprocessing/context.py
+++ b/Lib/multiprocessing/context.py
@@ -223,6 +223,10 @@ class Process(process.BaseProcess):
     def _Popen(process_obj):
         return _default_context.get_context().Process._Popen(process_obj)
 
+    @staticmethod
+    def _after_fork():
+        return _default_context.get_context().Process._after_fork()
+
 class DefaultContext(BaseContext):
     Process = Process
 
@@ -283,6 +287,11 @@ if sys.platform != 'win32':
             from .popen_spawn_posix import Popen
             return Popen(process_obj)
 
+        @staticmethod
+        def _after_fork():
+            # process is spawned, nothing to do
+            pass
+
     class ForkServerProcess(process.BaseProcess):
         _start_method = 'forkserver'
         @staticmethod
@@ -326,6 +335,11 @@ else:
             from .popen_spawn_win32 import Popen
             return Popen(process_obj)
 
+        @staticmethod
+        def _after_fork():
+            # process is spawned, nothing to do
+            pass
+
     class SpawnContext(BaseContext):
         _name = 'spawn'
         Process = SpawnProcess
diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py
index 3917d2e..c03c859 100644
--- a/Lib/multiprocessing/process.py
+++ b/Lib/multiprocessing/process.py
@@ -304,8 +304,7 @@ class BaseProcess(object):
             if threading._HAVE_THREAD_NATIVE_ID:
                 threading.main_thread()._set_native_id()
             try:
-                util._finalizer_registry.clear()
-                util._run_after_forkers()
+                self._after_fork()
             finally:
                 # delay finalization of the old process object until after
                 # _run_after_forkers() is executed
@@ -336,6 +335,13 @@ class BaseProcess(object):
 
         return exitcode
 
+    @staticmethod
+    def _after_fork():
+        from . import util
+        util._finalizer_registry.clear()
+        util._run_after_forkers()
+
+
 #
 # We subclass bytes to avoid accidental transmission of auth keys over network
 #