Hi,
Thank you Michal for your advice.
I went ahead and used gdb, and this is the result I got:

2014-02-14 00:54:11.109+0000: 34958: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58466,uid:0
2014-02-14 00:54:11.125+0000: 34958: error : qemudDomainInterfaceStats:7865 : 無効な引数: 無効なパス、'Interface' は不明なインターフェイスです
2014-02-14 00:54:11.155+0000: 34960: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58474,uid:0
2014-02-14 00:54:11.218+0000: 34967: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58489,uid:0
2014-02-14 00:54:11.282+0000: 34961: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58506,uid:0
2014-02-14 00:54:11.392+0000: 34967: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58514,uid:0
2014-02-14 00:54:11.408+0000: 34967: error : qemudDomainInterfaceStats:7865 : 無効な引数: 無効なパス、'Interface' は不明なインターフェイスです
2014-02-14 00:54:11.438+0000: 34960: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58522,uid:0
2014-02-14 00:54:11.502+0000: 34959: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58536,uid:0
2014-02-14 00:54:11.612+0000: 34961: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58573,uid:0
2014-02-14 00:54:11.707+0000: 34960: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58600,uid:0
2014-02-14 00:54:12.007+0000: 34962: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58642,uid:0
2014-02-14 00:54:12.072+0000: 34958: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58653,uid:0
2014-02-14 00:54:12.197+0000: 34960: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58666,uid:0
2014-02-14 00:54:12.264+0000: 34966: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58678,uid:0
2014-02-14 00:54:12.355+0000: 34967: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58685,uid:0
2014-02-14 00:54:12.508+0000: 34964: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58693,uid:0
2014-02-14 00:54:12.677+0000: 34961: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58707,uid:0
2014-02-14 00:54:12.744+0000: 34960: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58719,uid:0
2014-02-14 00:54:12.843+0000: 34965: info : remoteDispatchAuthList:2091 : Bypass polkit auth for privileged client pid:58726,uid:0

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f77cd80d700 (LWP 34958)]
0x00007f77d81b696c in free () from /lib64/libc.so.6

Here's the result of the backtrace:

(gdb) backtrace
#0 0x00007f77d81b696c in free () from /lib64/libc.so.6
#1 0x00007f77db790159 in virFree (ptrptr=0x7f77a0020088) at util/memory.c:310
#2 0x00007f77db7a1072 in virTypedParameterArrayClear (params=<value optimized out>,
    nparams=5) at util/virtypedparam.c:58
#3 0x0000000000425bec in remoteDispatchDomainBlockStatsFlags (
    server=<value optimized out>, client=<value optimized out>,
    msg=<value optimized out>, rerr=0x7f77cd80cbc0, args=<value optimized out>,
    ret=0x7f77a0021730) at remote.c:1186
#4 remoteDispatchDomainBlockStatsFlagsHelper (server=<value optimized out>,
    client=<value optimized out>, msg=<value optimized out>, rerr=0x7f77cd80cbc0,
    args=<value optimized out>, ret=0x7f77a0021730) at remote_dispatch.h:757
#5 0x00007f77db856e65 in virNetServerProgramDispatchCall (prog=0xf1f220,
    server=0xf13ce0, client=0xf1b570, msg=0xf1f3d0) at rpc/virnetserverprogram.c:416
#6 virNetServerProgramDispatch (prog=0xf1f220, server=0xf13ce0, client=0xf1b570,
    msg=0xf1f3d0) at rpc/virnetserverprogram.c:289
#7 0x00007f77db8580f1 in virNetServerHandleJob (jobOpaque=<value optimized out>,
    opaque=0xf13ce0) at rpc/virnetserver.c:164
#8 0x00007f77db79a45c in virThreadPoolWorker (opaque=<value optimized out>)
    at util/threadpool.c:144
#9 0x00007f77db799d79 in virThreadHelper (data=<value optimized out>)
    at util/threads-pthread.c:161
#10 0x00007f77d88dc851 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f77d822367d in clone () from /lib64/libc.so.6

And util/virtypedparam.c:58 looks like this for libvirt-0.9.10:
49 virTypedParameterArrayClear(virTypedParameterPtr params, int nparams)
50 {
51     int i;
52
53     if (!params)
54         return;
55
56     for (i = 0; i < nparams; i++) {
57         if (params[i].type == VIR_TYPED_PARAM_STRING)
58             VIR_FREE(params[i].value.s);
59     }
60 }
61

I'm very unfamiliar with C so I would again appreciate any input on why this is happening, and what I can do to solve this issue.
By the way this segfault can be 100% reproduced with CentOS 6.3 but not CentOS 6.2.

Thank you and regards,
Minami

On 2014/02/07 18:30, Michal Privoznik wrote: