当通过ssh连接时,Maver上的GDB不起作用

Question

我在小牛队安装了一个brew版本的gdb.它是编码签名的,我可以在本地连接时调试没有问题:

$ gdb myprog
GNU gdb (GDB) 7.7.1
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin13.3.0".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from myprog...done.
(gdb) b main
Breakpoint 1 at 0x1000028e6: file main.c, line 38.
(gdb) r
Starting program: myprog 

Breakpoint 1, main (argc=1, argv=0x7fff5fbffae8) at main.c:38
38      float   pi=4.*(float)atan((double)1.);

但是,如果我首先使用ssh连接到主机,gdb现在不再起作用:

$ ssh localhost
Last login: Tue Jul 15 11:57:44 2014 from localhost
$ gdb myprog
GNU gdb (GDB) 7.7.1
blah blah...
Reading symbols from myprog...done.
(gdb) b main
Breakpoint 1 at 0x1000028e6: file main.c, line 38.
(gdb) r
Starting program: myprog 
Unable to find Mach task port for process-id 826: (os/kern) failure (0x5).
 (please check gdb is codesigned - see taskgated(8))
(gdb)

有谁知道为什么会发生这种情况以及如何解决它？