[Dovecot] Managesieve: Remote login fails

[Timo Sirainen]

On Nov 10, 2008, at 12:12 AM, Brainkiller - Tom wrote:

>>> This is a segmentation fault (crash) and therefore definitely a  
>>> bug in the ManageSieve service. But without more information I  
>>> cannot fix find and fix this bug. You should try to obtain a core  
>>> dump or a gdb trace as explained at http://dovecot.org/bugreport.html 
>>>  . Debugging the login daemons can be a little more tricky. I  
>>> usually attach gdb to the managesieve-login process that is  
>>> handling my connection (using the gdb attach command). Be sure to  
>>> compile dovecot with debugging symbols enabled (default Debian  
>>> packages are stripped).
>>>
>>> It is also interesting to know when exactly during the login  
>>> process it crashes. If you login manually from a remote host (as  
>>> explained in section 6 of http://wiki.dovecot.org/ManageSieve) you  
>>> will be able to check where it crashes. If you do not use TLS, you  
>>> can also sniff the traffic between client and server using ngrep  
>>> to see where the login process dies.
>>>
>>> Regards,
>>>
> Hello again,
>
> I tried to get a coredump with the infromation an the provided web- 
> page. However i never got a dump.

You can't get core dumps easily from login processes. The easiest way  
to get a backtrace is:

1. Set login_processes_count = 1
2. Restart Dovecot and make sure you have only a single managesieve- 
login process.
3. gdb -p `pidof managesieve-login`
4. Give "c" command to gdb.
5. Log in, causing the crash
6. gdb should have now stopped, give it "bt full" command.

> I used the packages provided by "deb http://xi.rename-it.nl/debian/  
> testing-auto main". I don't know if these contain the debugging  
> symbols. So it seems i can't provide any further information.

Even without debugging symbols you should be able to get some kind of  
a backtrace.
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