Handle RuntimeError when attaching to a process in pdb.py

Signed-off-by: Frost Ming <me@frostming.com>

Lib/pdb.py

@@ -3577,6 +3577,11 @@ def main():
             parser.error("argument -m: not allowed with argument --pid")
         try:
             attach(opts.pid, opts.commands)
+        except RuntimeError as e:
+            while e.__context__ is not None:
+                e = e.__context__
+            print(f"Error attaching to process: {e}")
+            sys.exit(1)
         except PermissionError as e:
             exit_with_permission_help_text()
         return