Add extended mode to prevent service from dying.

lib/msf/core/exploit/gdb.rb

@@ -158,6 +158,11 @@ module Exploit::Remote::Gdb
     read_response
   end
 
+  def enable_extended_mode
+    send_cmd("!")
+    read_response
+  end
+
   # Performs a handshake packet exchange
   # @param features [String] the list of supported features to tell the remote
   #   host that the client supports (defaults to +DEFAULT_GDB_FEATURES+)

modules/exploits/multi/gdb/gdb_server_exec.rb

@@ -43,6 +43,8 @@ class Metasploit3 < Msf::Exploit::Remote
     print_status "Performing handshake with gdbserver..."
     handshake
 
+    enable_extended_mode
+
     begin
       print_status "Stepping program to find PC..."
       gdb_data = process_info