tests/functional: ensure GDB client is stopped on error

If the reverse_debugging_run method fails, the GDB client will not
be closed resulting in python complaining about resource leaks.
Hoisting the GDB client creation into the caller allows this to
be cleaned up easily. While doing this, also move the VM shutdown
call to match.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20251014140047.385347-3-berrange@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/functional/reverse_debugging.py

@@ -96,7 +96,14 @@ class ReverseDebugging(LinuxKernelTest):
 
         try:
             self.log.info('Connecting to gdbstub...')
-            self.reverse_debugging_run(vm, port, gdb_arch, last_icount)
+            gdb_cmd = os.getenv('QEMU_TEST_GDB')
+            gdb = GDB(gdb_cmd)
+            try:
+                self.reverse_debugging_run(gdb, vm, port, gdb_arch, last_icount)
+            finally:
+                self.log.info('exiting gdb and qemu')
+                gdb.exit()
+                vm.shutdown()
             self.log.info('Test passed.')
         except GDB.TimeoutError:
             # Convert a GDB timeout exception into a unittest failure exception.
@@ -107,10 +114,7 @@ class ReverseDebugging(LinuxKernelTest):
             # skipTest(), etc.
             raise
 
-    def reverse_debugging_run(self, vm, port, gdb_arch, last_icount):
-        gdb_cmd = os.getenv('QEMU_TEST_GDB')
-        gdb = GDB(gdb_cmd)
-
+    def reverse_debugging_run(self, gdb, vm, port, gdb_arch, last_icount):
         r = gdb.cli("set architecture").get_log()
         if gdb_arch not in r:
             self.skipTest(f"GDB does not support arch '{gdb_arch}'")
@@ -191,7 +195,3 @@ class ReverseDebugging(LinuxKernelTest):
             self.fail("'reverse-continue' did not hit the first PC in reverse order!")
 
         self.log.info('successfully reached %x' % steps[-1])
-
-        self.log.info('exiting gdb and qemu')
-        gdb.exit()
-        vm.shutdown()