[Dovecot] Managesieve: Remote login fails

[Brainkiller - Tom]

Timo Sirainen schreef:
> 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.
Thanks, I now have a full stacktrace however since i didn't have any 
debugging symbols so I think it won't be of any use. If the output below 
is off any use please let me know otherwise I'll try to get some time 
somewhere to install a version with debugging symbols.

GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
Attaching to process 27247
Reading symbols from /usr/lib/dovecot/managesieve-login...(no debugging 
symbols found)...done.
Reading symbols from /usr/lib/i686/cmov/libssl.so.0.9.8...(no debugging 
symbols found)...done.
Loaded symbols for /usr/lib/i686/cmov/libssl.so.0.9.8
Reading symbols from /usr/lib/i686/cmov/libcrypto.so.0.9.8...(no 
debugging symbols found)...done.
Loaded symbols for /usr/lib/i686/cmov/libcrypto.so.0.9.8
Reading symbols from /lib/i686/cmov/libc.so.6...(no debugging symbols 
found)...done.
Loaded symbols for /lib/i686/cmov/libc.so.6
Reading symbols from /lib/i686/cmov/libdl.so.2...(no debugging symbols 
found)...done.
Loaded symbols for /lib/i686/cmov/libdl.so.2
Reading symbols from /usr/lib/libz.so.1...(no debugging symbols 
found)...done.
Loaded symbols for /usr/lib/libz.so.1
Reading symbols from /lib/ld-linux.so.2...
(no debugging symbols found)...done.
Loaded symbols for /lib/ld-linux.so.2
(no debugging symbols found)
0xffffe424 in __kernel_vsyscall ()
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x08072fba in ?? ()
(gdb) bt full
#0  0x08072fba in ?? ()
No symbol table info available.
#1  0x0806c9b6 in ?? ()
No symbol table info available.
#2  0x080989a0 in ?? ()
No symbol table info available.
#3  0x00000000 in ?? ()
No symbol table info available.
(gdb)


Regards, Tom