gh-140729: Fix the cProfile module when the executed script contains calls to multiprocessing.Process

Lib/profiling/tracing/__init__.py

@@ -197,7 +197,10 @@ def main():
             # in the module's namespace.
             globs = module.__dict__
             globs.update({
-                '__spec__': spec,
+                # See gh-140729, set None to __spec__ according
+                # to the documentation,
+                # https://docs.python.org/3/reference/import.html#module-specs
+                '__spec__': None,
                 '__file__': spec.origin,
                 '__name__': spec.name,
                 '__package__': None,

Lib/test/test_profiling/test_sampling_profiler/test_advanced.py

@@ -234,3 +234,50 @@ def worker(x):
 
         self.assertIn("Results: [2, 4, 6]", stdout)
         self.assertNotIn("Can't pickle", stderr)
+
+
+@requires_remote_subprocess_debugging()
+class TestProcessRunSupport(unittest.TestCase):
+    """
+    Test that Process works correctly with cProfile.
+    """
+
+    def test_process_run_pickle(self):
+        # gh-140729: test use Process in cProfile.
+        val = 10
+        test_script = f'''
+import multiprocessing
+
+def worker(x):
+    print(__name__)
+    exit(x ** 2)
+
+if __name__ == "__main__":
+    multiprocessing.set_start_method("spawn")
+    p = multiprocessing.Process(target=worker, args=({val},))
+    p.start()
+    p.join()
+    print("p.exitcode =", p.exitcode)
+'''
+
+        with os_helper.temp_dir() as temp_dir:
+            script = script_helper.make_script(
+                temp_dir, 'test_process_run_pickle', test_script
+            )
+            with SuppressCrashReport():
+                with script_helper.spawn_python(
+                    "-m", "cProfile",
+                    script,
+                    stdout=subprocess.PIPE,
+                    stderr=subprocess.PIPE,
+                    text=True
+                ) as proc:
+                    try:
+                        stdout, stderr = proc.communicate(timeout=SHORT_TIMEOUT)
+                    except subprocess.TimeoutExpired:
+                        proc.kill()
+                        stdout, stderr = proc.communicate()
+
+        self.assertIn("__mp_main__", stdout)
+        self.assertIn(f"exitcode = {val**2}", stdout)
+        self.assertNotIn("Can't pickle", stderr)

Misc/NEWS.d/next/Library/2026-02-11-16-47-27.gh-issue-140729.2uTPQp.rst

@@ -0,0 +1,2 @@
+Fix pickling error in the cProfile module when using ``multiprocessing.Process``
+script, which can not be properly pickled and executed.