[SSSD-users] Startup segfault loop of domain_be on Ubuntu 14.04

Jakub Hrozek jhrozek at redhat.com
Thu Aug 14 06:41:06 UTC 2014


On Wed, Aug 13, 2014 at 07:08:33PM +0200, Lukas Slebodnik wrote:
> On (13/08/14 11:12), Chris Hartman wrote:
> >Greetings,
> >
> >Could you send me more coredumps privately with fuly updated ubuntu 14.04?
> >> Because it really strange that sssd crashed in syscal fdatasync.
> >
> >Lukas, not a problem. Stand by for an email with a 7zip archive of a core
> >dump and back trace. The debugging symbols for lib{tdb,ldb}1 were installed
> >for this.
> >
> >I have another idea which could help us to to find a problem.
> >> We can try to run sssd_be with valgrind.
> >> 1) we need to find out arguments for process sssd_be
> >> sh-4.2$ pgrep -af sssd_be
> >> 1191 /usr/libexec/sssd/sssd_be --domain idm.example.com --debug-to-files
> >>      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> >>      this output will be used in sssd.conf
> >> 2) add new option to domain section in sssd.conf
> >> command = valgrind -v --show-reachable=yes --log-file=/var/log/sssd/valgrind_idm.example.com.log
> >> /usr/libexec/sssd/sssd_be --domain idm.example.com --debug-to-files
> >>     # do not forget to replace output from previous step.
> >>
> >> 3) It would be good to install debug symbols for libraries libtdb1 and
> >> libldb1
> >> 4) reproduce problem
> >>     some interesting output can be in log file from valgrind.
> >
> > I did this with interesting(?) results. The sssd_be process never actually
> >crashed but there is some erroneous output in the valgrind log. Removing
> >the special command option results in a crash as expected. I've sanitized
> >and attached the log to this email. Let me know if that reveals anything.
> >
> Thank you very much for log files from valgrind.
> There is use after free problem in dynamic dns updates code.
> 
> Could you try to disable dynamic dns updates in domain section.
>     dyndns_update = false
> 
> LS

Thank you very much for debugging, Chris!

I filed https://fedorahosted.org/sssd/ticket/2405 to track this problem.


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