free野指针问题

gdb backtrace内容如下：

 Program received signal SIGABRT, Aborted.

 0xb67683c0 in raise () from /lib/libc.so.

 (gdb) p cmd

 No symbol "cmd" in current context.

 (gdb) bt

 #  0xb67683c0 in raise () from /lib/libc.so.

 #  0xb6762bfc in abort () from /lib/libc.so.

 8 #2  0xb67626a8 in free () from /lib/libc.so.0

 9 #3  0xb6a8a6dc in cmd_matcher_match_keyword (matcher=0xbeac7080, token=0x917690, argc=0xbeac7698, argv=0xbeac7634)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

 #  0xb6a8a97c in cmd_element_match (cmd_element=0xb65d02ec, filter=FILTER_RELAXED, vline=0x8ec160, index=,

     match_type=0x0, match=0x0, argc=0xbeac7698, argv=0xbeac7634)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

 #  0xb6a8ace4 in cmd_parse (cmd_element=0xb65d02ec, vline=0x8ec160, argc=0xbeac7698, argv=0xbeac7634)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

 #  0xb6a8d680 in cmd_execute_command_real (vline=0x8ec160, filter=FILTER_RELAXED, vty=0x8dd290, cmd=0xbeac7798)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

 #  0xb6a8e564 in cmd_execute_command (vline=0x8ec160, vty=0x8dd290, cmd=0xbeac7798, vtysh=)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

 #  0x000278f0 in vtysh_execute_func (line=0x977c8f "snmp-server host 10.54.88.108 inform version v2c community a3 port 162",

     pager=) at /Source_route/wns/apps/openswitch_ori/ops-cli/vtysh/vtysh.c:

 #  0x00027ec0 in vtysh_execute (line=0x977c8f "snmp-server host 10.54.88.108 inform version v2c community a3 port 162")

     at /Source_route/wns/apps/openswitch_ori/ops-cli/vtysh/vtysh.c:

 # 0x00025e80 in s_process_cli_cmd (buf=0x985860, len=, msg=0x0, proxy_hdr=0x98581c)

     at /Source_route/wns/apps/openswitch_ori/ops-cli/vtysh/vtysh_main.c:

 # 0xb6a29a28 in ?? () from /wns/lib/libwns_ipc.so

 # 0xb6a29a28 in ?? () from /wns/lib/libwns_ipc.so

 Backtrace stopped: previous frame identical to this frame (corrupt stack?)

看第2、3行， 在cmd_matcher_match_keyword 函数中free出错，有两种情况：释放野指针；重复释放（造成野指针）

所以，在看看前文哪里有free行为的代码， 直接注释掉

---

(gdb) frame

#  0xb6b326dc in cmd_matcher_match_keyword (matcher=0xbec3d080, token=0xb3b690, argc=0xbec3d698, argv=0xbec3d634) at /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c:

    in /Source_route/wns/apps/openswitch_ori/ops-cli/lib/command.c

(gdb) ptype matcher

type = struct cmd_matcher {

    struct cmd_element *cmd;

    enum filter_type filter;

    vector vline;

    unsigned int index;

    enum match_type *match_type;

    vector *match;

    unsigned int word_index;

} *

(gdb)

frame n切换现场查看具体信息