[ltt-dev] UST - Problems in recording trace on a current process

[Pierre-Marc Fournier]

On February 10, 2010 11:53:12 Naren wrote:
> Hi Pierre
>
> >>I'm not sure what you could have done that would necessitate a clean
> >>install. If you suspect your installation is dirty or composed of libs
> >>of mixed versions, I suggest to do clean install as the situation can
> >>result in segfaults.
> >>
> >>But you might face a real bug. Based on the strace output, it is ustctl
> >>that is segfaulting. Could you compile it with:
> >>
> >>make clean
> >>CFLAGS="-g3" ./configure
> >>make
> >>make install
> >>
> >>Then run the same ustctl command within gdb and post the backtrace (bt
> >>command) you get after the segfault.
>
> As suggested, I did a back trace on ustctl. Prior to that, i did a clean
> install and configured ust with flags on. Here is the stackdump produced by
> bt.
>
> *(gdb) bt full*
> *#0  0x0804ddef in ustcmd_get_cmsf (cmsf=0xbffff35c, pid=5189)*
> *    at ../libustcmd/ustcmd.c:284*
> *        state = 49 '1'*
> *        big_str = 0x8052018 "marker: metadata/core_marker_format 1
> \"channel %s name %s format %s\" 0xb7ee3c6a\nmarker:
> metadata/core_marker_format 1 \"channel %s name %s format %s\"
> 0xb7ee4bb0\nmarker: metadata/core_marker_id 1 \"chann"...*
> *        result = 0*
> *        tmp_cmsf = 0x8052408*
> *        i = 135144*
> *        cmsf_ind = 13*
> *#1  0x08049cff in main (argc=3, argv=0xbffff534) at ustctl.c:267*
> *        i = 0*
> *        pidit = 0x8052008*
> *        result = 0*
> *        opts = {cmd = LIST_MARKERS, pids = 0x8052008, regex = 0x0}*
> *        cmsf = 0x0*
> *        __func__ = "main"*
> *(gdb) *
>

I just commited a quick and dirty fix for this issue. A refactoring of the ust 
communication lib is in progress to address this more elegantly.

Thanks for the report!

pmf