samba - Aug 2015 - FW: Questions about Samba 4

On 08/26/2015 02:21 PM, Rowland Penny wrote:
> On 26/08/15 22:13, Jeremy Allison wrote:
>> On Wed, Aug 26, 2015 at 09:46:48PM +0100, Rowland Penny wrote:
>>>> ... 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.
>>> OK, does '(no debugging symbols found)' mean what I think
it means ?
>>> i.e. winbindd wasn't built with -g
>> Yep :-(.
>>
>>> ... stuff I'm interested in... is just:
>>>
>>>   (gdb) bt
>>> #0  0x00007f8d0cf0b12f in ?? ()
>>> #1  0x0000000000000000 in ?? ()
>>> (gdb)
>> Yeah, that doesn't help :-).
>>
>>> If this is what you are looking for I will add it to the bug report
>>> 11038, if not, I will have to download the src deb for winbindd and
>>> rebuild it with -g , but this will have to wait until tomorrow.
>> OK, no problem. Rebuilding with -g is what is needed here.
>>
>> The other thing that helps is to attach to the process
>> using strace,
>>
>>
>> # strace -p WINBINDD_SPINNING_PID
>>
>> - which should give a looping amount of system call
>> output which would also be helpful.
> 
> OK, I have downloaded the source and looking at debian/rules file (which
> seems to have been written by someone called Jelmer Vernooij (where have
> heard that name before ?)) I think I need to add '--enable-debug'
to the
> 'conf_args' list, but there is also this:
> 
> override_dh_strip:
>         # add debug symbols for all samba packages to the same debug
> package
>         dh_strip -a --dbg-package=samba-dbg
> 
> Do I need to do anything with this ?
> 
> Rowland
> 
> 
Install the "samba-dbg" package. It contains the debug symbols. Once
installed, restart winbind, and try using gdb again.

-- 
John Yocum, Systems Administrator, DEOHS

On 26/08/15 22:31, John Yocum wrote:
> On 08/26/2015 02:21 PM, Rowland Penny wrote:
>> On 26/08/15 22:13, Jeremy Allison wrote:
>>> On Wed, Aug 26, 2015 at 09:46:48PM +0100, Rowland Penny wrote:
>>>>> ... 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.
>>>> OK, does '(no debugging symbols found)' mean what I
think it means ?
>>>> i.e. winbindd wasn't built with -g
>>> Yep :-(.
>>>
>>>> ... stuff I'm interested in... is just:
>>>>
>>>>    (gdb) bt
>>>> #0  0x00007f8d0cf0b12f in ?? ()
>>>> #1  0x0000000000000000 in ?? ()
>>>> (gdb)
>>> Yeah, that doesn't help :-).
>>>
>>>> If this is what you are looking for I will add it to the bug
report
>>>> 11038, if not, I will have to download the src deb for winbindd
and
>>>> rebuild it with -g , but this will have to wait until tomorrow.
>>> OK, no problem. Rebuilding with -g is what is needed here.
>>>
>>> The other thing that helps is to attach to the process
>>> using strace,
>>>
>>>
>>> # strace -p WINBINDD_SPINNING_PID
>>>
>>> - which should give a looping amount of system call
>>> output which would also be helpful.
>> OK, I have downloaded the source and looking at debian/rules file
(which
>> seems to have been written by someone called Jelmer Vernooij (where
have
>> heard that name before ?)) I think I need to add
'--enable-debug' to the
>> 'conf_args' list, but there is also this:
>>
>> override_dh_strip:
>>          # add debug symbols for all samba packages to the same debug
>> package
>>          dh_strip -a --dbg-package=samba-dbg
>>
>> Do I need to do anything with this ?
>>
>> Rowland
>>
>>
> Install the "samba-dbg" package. It contains the debug symbols.
Once
> installed, restart winbind, and try using gdb again.
>
Thanks for the hint, but it didn't work, still got lots of '(no 
debugging symbols found)' and the same result as before. What I did 
notice was when I tried 'strace -p WINBINDD_SPINNING_PID' I only got 
'Process 3980 attached'
in the output and the 'WINBINDD_SPINNING_PID' dropped out of the
'top'
screen, does this mean anything ?

Anyway, I will rebuild samba tomorrow and try again.

Rowland

On Wed, Aug 26, 2015 at 11:01:40PM +0100, Rowland Penny
wrote:
> 
> Thanks for the hint, but it didn't work, still got lots of '(no
> debugging symbols found)' and the same result as before. What I did
> notice was when I tried 'strace -p WINBINDD_SPINNING_PID' I only
got
> 'Process 3980 attached'
> in the output and the 'WINBINDD_SPINNING_PID' dropped out of the
> 'top' screen, does this mean anything ?
Yes, actually - thanks ! It means internal data
structures got corrupted and it's almost certainly
spinning in a tight loop walking a (looped) linked
list and not doing any system calls.

Useful data, thanks !

Is there still extra data needed to debug? 
I saw Rowland tested on debian wheezy and mint (ubuntu 4.1.6) 

I tested on a debian Jessie with sernet samba 4.2.3. member server. 
I can test also on a debian jessie with 4.1.17. member server.

Greetz, 

Louis


>-----Oorspronkelijk bericht-----
>Van: samba [mailto:samba-bounces at lists.samba.org] Namens Jeremy Allison
>Verzonden: donderdag 27 augustus 2015 00:07
>Aan: Rowland Penny
>CC: samba at lists.samba.org
>Onderwerp: Re: [Samba] FW: Questions about Samba 4
>
>On Wed, Aug 26, 2015 at 11:01:40PM +0100, Rowland Penny wrote:
>> 
>> Thanks for the hint, but it didn't work, still got lots of '(no
>> debugging symbols found)' and the same result as before. What I did
>> notice was when I tried 'strace -p WINBINDD_SPINNING_PID' I
only got
>> 'Process 3980 attached'
>> in the output and the 'WINBINDD_SPINNING_PID' dropped out of
the
>> 'top' screen, does this mean anything ?
>
>Yes, actually - thanks ! It means internal data
>structures got corrupted and it's almost certainly
>spinning in a tight loop walking a (looped) linked
>list and not doing any system calls.
>
>Useful data, thanks !
>
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