[libvirt] gdb works abnormally when debug the libvirt.

[ShaoHe Feng]

thank you. It can work.
, Michal Privoznik wrote:
> On 29.11.2011 11:32, ShaoHe Feng wrote:
>> When I  to use gdb to check whether qemuMonitorJSONIOProcessEvent
>> processes the Event that I expect.
>>
>> but the gdb works  abnormally.
>> I list the the position of the source file by gdb. It is the correct
>> functionqemuMonitorJSONIOProcessEvent.
>> However I set break point on this  position. then "info b", it is the
>> wrong function qemuMonitorJSONIOProcess.
>>
>> I debug my libvirt on Ubuntu 11.10 this time.But I have set  a break
>> point at this function on redhat 6.0 before, it can work well.
>>
>> My gcc version is: gcc (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1
>> My gdb version is: GNU gdb (Ubuntu/Linaro 7.3-0ubuntu2) 7.3-2011.08
>>
>> here is the info:
>>
>> (gdb) list qemu/qemu_monitor_json.c:88
>> 83    qemuMonitorJSONIOProcessEvent(qemuMonitorPtr mon,
>> 84                                  virJSONValuePtr obj)
>> 85    {
>> 86        const char *type;
>> 87        int i;
>> 88        int findEventFlag = -1;
>> 89        VIR_DEBUG("mon=%p obj=%p", mon, obj);
>> 90   
>> 91        type = virJSONValueObjectGetString(obj, "event");
>> 92        if (!type) {
>>
>>
>>
>> (gdb) b qemu/qemu_monitor_json.c:88
>> Breakpoint 5 at 0x4a18d4: file qemu/qemu_monitor_json.c, line 88.
>> (gdb) info b
>> Num     Type           Disp Enb Address            What
>> 5       breakpoint     keep y   0x00000000004a18d4 in
>> qemuMonitorJSONIOProcess at qemu/qemu_monitor_json.c:88
>> (gdb)
>>
>>
> This may be caused by libvirtd being compiled with -O2; You want to turn
> that off:
> 1) get libvirt sources, unpack them and cd <unpacked sources>
> 2) export CFLAGS='-O0'
> 3) ./autogen --system && make
>
> Now you should have libvirtd in ./daemon/libvirtd; However, this is
> libtool wrapper script. So you won't succeed running it directly (gdb
> ./daemon/libvirtd); I personally use attach: gdb -p $(pgrep libvirtd);
> NB, you should shutdown your system libvirtd: service libvirtd shutdown
>
> Michal
>