[Samba] FW: Questions about Samba 4

[Jeremy Allison]

On Wed, Aug 26, 2015 at 09:02:03PM +0100, Rowland Penny wrote:
> On 26/08/15 20:54, Jeremy Allison wrote:
> >On Wed, Aug 26, 2015 at 08:45:29PM +0100, Rowland Penny wrote:
> >>On 26/08/15 19:39, Volker Lendecke wrote:
> >>>On Wed, Aug 26, 2015 at 05:44:44PM +0200, L.P.H. van Belle wrote:
> >>>>ok, i cant make i crash. but i notice my cpu load.
> >>>>
> >>>>17535 username     20   0  294852  13716  11520 R 100.0  1.3 280:28.70 winbindd
> >>>>   542 username     20   0  291040  16720  14172 R  99.6  1.6 281:45.88 winbindd
> >>>>
> >>>>and the funny thing.. this user isnt logged in anymore since the last 6 hours.
> >>>What is the exact environment this is running on?
> >>>
> >>>Thanks,
> >>>
> >>>Volker
> >>>
> >>OK, I can confirm that if you set a user to change their password at
> >>next login and then try to login to a member server via SSH as that
> >>user, winbind runs the CPU on the member server up to 100% and you
> >>have to kill winbind (I actually had to use kill -9 on 4 different
> >>PIDs as they popped up).
> >>
> >>OK, what info do you want and how do I get it, please be explicit,
> >>don't just say something like 'attach to x with xyz'
> >>
> >>DC: wheezy, Samba Version 4.1.17-Debian
> >>Member Server: Linux Mint, Samba Version 4.1.6-Ubuntu
> >Thanks Rowland, can you attach to one of the
> >spinning winbindd processes via gdb and get
> >a backtrace and upload to the bug report ?
> >
> >Cheers,
> >
> >	Jeremy.
> 
> Jeremy, please don't take this the wrong way, but what part of of
> 'please be explicit' do you not understand ? :-D

Oh, sorry. All if it I guess :-).

> I have not got a clue how to attach to one of the spinning winbindd
> processes via gdb.
> 
> If you could please explain just how to do this, I will do it and
> then put something about using gdb on the wiki.

OK, find the process id of the spinning winbindd using the 'top'
command - call it PID_SPIN.

Become root.

Type:

gdb /usr/sbin/winbindd
...
(gdb) attach PID_SPIN
...
(gdb) bt

... stuff I'm interested in...

Then paste the "... stuff I'm interested in..."
output into the bug report.

I'm assuming winbindd has been built with -g (DEBUG)
turned on.