More fixes

Lib/test/test_sample_profiler.py

@@ -1634,15 +1634,18 @@ def test_invalid_output_format_with_mocked_profiler(self):
             )
 
     def test_is_process_running(self):
-        with (test_subprocess("import time; time.sleep(1000)") as proc,
-              mock.patch("_remote_debugging.RemoteUnwinder") as mock_unwinder_class):
-                mock_unwinder_class.return_value = mock.MagicMock()
-                profiler = SampleProfiler(pid=proc.pid, sample_interval_usec=1000, all_threads=False)
-                self.assertTrue(profiler._is_process_running())
-                proc.kill()
+        with test_subprocess("import time; time.sleep(1000)") as proc:
+            profiler = SampleProfiler(pid=proc.pid, sample_interval_usec=1000, all_threads=False)
+            self.assertTrue(profiler._is_process_running())
+            self.assertIsNotNone(profiler.unwinder.get_stack_trace())
+            proc.kill()
+            proc.wait()
+            # ValueError on MacOS (yeah I know), ProcessLookupError on Linux and Windows
+            self.assertRaises((ValueError, ProcessLookupError), profiler.unwinder.get_stack_trace)
 
         # Exit the context manager to ensure the process is terminated
         self.assertFalse(profiler._is_process_running())
+        self.assertRaises((ValueError, ProcessLookupError), profiler.unwinder.get_stack_trace)
 
     @unittest.skipUnless(sys.platform == "linux", "Only valid on Linux")
     def test_esrch_signal_handling(self):

Python/remote_debug.h

@@ -720,6 +720,14 @@ search_linux_map_for_section(proc_handle_t *handle, const char* secname, const c
 
 #ifdef MS_WINDOWS
 
+static int is_process_alive(HANDLE hProcess) {
+    DWORD exitCode;
+    if (GetExitCodeProcess(hProcess, &exitCode)) {
+        return exitCode == STILL_ACTIVE;
+    }
+    return 0;
+}
+
 static void* analyze_pe(const wchar_t* mod_path, BYTE* remote_base, const char* secname) {
     HANDLE hFile = CreateFileW(mod_path, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
     if (hFile == INVALID_HANDLE_VALUE) {
@@ -950,6 +958,13 @@ _Py_RemoteDebug_ReadRemoteMemory(proc_handle_t *handle, uintptr_t remote_address
     SIZE_T result = 0;
     do {
         if (!ReadProcessMemory(handle->hProcess, (LPCVOID)(remote_address + result), (char*)dst + result, len - result, &read_bytes)) {
+            // Check if the process is still alive: we need to be able to tell our caller
+            // that the process is dead and not just that the read failed.
+            if (!is_process_alive(handle->hProcess)) {
+                _set_errno(ESRCH);
+                PyErr_SetFromErrno(PyExc_OSError);
+                return -1;
+            }
             PyErr_SetFromWindowsErr(0);
             DWORD error = GetLastError();
             _set_debug_exception_cause(PyExc_OSError,