diff --git a/gdbstub.c b/gdbstub.c
index 2c7032f53a..9b6b4d20a0 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1302,6 +1302,9 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
     p = line_buf;
     ch = *p++;
     switch(ch) {
+    case '!':
+        put_packet(s, "OK");
+        break;
     case '?':
         /* TODO: Make this return the correct value for user-mode.  */
         snprintf(buf, sizeof(buf), "T%02xthread:%s;", GDB_SIGNAL_TRAP,