On 08/16/2011 04:42 PM, Kostas Zorbadelos wrote:
On 08/15/2011 11:17 AM, kzo...@otenet.gr wrote:
Quoting Timo Sirainen<t...@iki.fi>:


OK,

we managed to reproduce the problem with the following scenario.

Using Thunderbird (3.1.11 if that matters) we set up a mail account using POP served by dovecot. In the account settings we have checked the boxes "Leave messages on server" and "Until I delete them" which is the default setting for new accounts.

We make the first POP session and get the mails. We then delete a message (moving it to trash) and try to Get Mails. Dovecot crashes with the aforementioned stack trace (included below). If you again try Get Mail in the client, you get the deleted mail again.

It seems to be related to the indexing code since if we change the setting

mbox_min_index_size

to something bigger than the mailbox (so no cache index files are created) the problem does not appear and the mails get deleted from the server normally. We didn't manage to reproduce the problem with Microsoft Outlook.

We 'll keep investigating until we have a fix.

Regards,

Kostas

With a quick test I can't reproduce pop3_lock_session=yes causing a
crash. I guess it needs something else besides what I tested. It would
be helpful if your Dovecot binaries weren't stripped of debug symbols. I
could then ask for some more information from the core dumps with gdb.



Timo, all

here is a backtrace with debuging symbols in the executables:

[root@pop08 ]# gdb /opt/dovecot-debug/libexec/dovecot/pop3 core.2929
GNU gdb (GDB) Red Hat Enterprise Linux (7.0.1-32.el5_6.2)
Copyright (C) 2009 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 "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /opt/dovecot-debug/libexec/dovecot/pop3...done.
BFD: Warning: /var/mail7/folders/P/K/U/amihal/core.2929 is truncated: expected 
core file size>= 569344, found: 565248.
Reading symbols from 
/opt/dovecot-debug/lib/dovecot/libdovecot-storage.so.0...done.
Loaded symbols for /opt/dovecot-debug/lib/dovecot/libdovecot-storage.so.0
Reading symbols from /opt/dovecot-debug/lib/dovecot/libdovecot.so.0...done.
Loaded symbols for /opt/dovecot-debug/lib/dovecot/libdovecot.so.0
Reading symbols from /lib64/libdl.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib64/librt.so.1
Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols 
found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libpthread.so.0...(no debugging symbols 
found)...done.
Loaded symbols for /lib64/libpthread.so.0
Core was generated by `dovecot/pop3'.
Program terminated with signal 11, Segmentation fault.
#0  istream_raw_mbox_get_start_offset (stream=0x0) at istream-raw-mbox.c:498
498     istream-raw-mbox.c: No such file or directory.
         in istream-raw-mbox.c
(gdb) bt
#0  istream_raw_mbox_get_start_offset (stream=0x0) at istream-raw-mbox.c:498
#1  0x00002b4114afc769 in mbox_mail_get_special (_mail=0x1bad8fa0, field=<value 
optimized out>, value_r=0x7fff9600fa88) at mbox-mail.c:198
#2  0x00002b4114adb2d0 in index_mail_expunge (mail=0x0) at index-mail.c:1503
#3  0x0000000000405eac in client_update_mails (client=0x1bac4a00) at 
pop3-commands.c:255
#4  0x00000000004061d1 in cmd_quit (client=0x1bac4a00, name=0x1baccbd4 "", args=0x406a0c 
"") at pop3-commands.c:274
#5  client_command_execute (client=0x1bac4a00, name=0x1baccbd4 "", args=0x406a0c 
"") at pop3-commands.c:773
#6  0x00000000004045c9 in client_handle_input (client=0x1bac4a00) at 
pop3-client.c:628
#7  0x00002b4114db0698 in io_loop_call_io (io=0x1bac01d0) at ioloop.c:384
#8  0x00002b4114db19d5 in io_loop_handler_run (ioloop=<value optimized out>) at 
ioloop-epoll.c:213
#9  0x00002b4114db062d in io_loop_run (ioloop=0x1baa8610) at ioloop.c:405
#10 0x00002b4114d9ef13 in master_service_run (service=0x1baa84e0, 
callback=0x1baccbe4) at master-service.c:478
#11 0x00000000004039a4 in main (argc=1, argv=0x1baa8370) at main.c:252
(gdb) bt full
#0  istream_raw_mbox_get_start_offset (stream=0x0) at istream-raw-mbox.c:498
         rstream =<value optimized out>
         __FUNCTION__ = "istream_raw_mbox_get_start_offset"
#1  0x00002b4114afc769 in mbox_mail_get_special (_mail=0x1bad8fa0, field=<value 
optimized out>, value_r=0x7fff9600fa88) at mbox-mail.c:198
         mail =<value optimized out>
         mbox = 0x1bac97d0
         offset = 0
#2  0x00002b4114adb2d0 in index_mail_expunge (mail=0x0) at index-mail.c:1503
         value =<value optimized out>
         guid_128 = 
"\240\267\252\033\000\000\000\000\001\000\000\000\000\000\000"
#3  0x0000000000405eac in client_update_mails (client=0x1bac4a00) at 
pop3-commands.c:255
         search_args = 0x0
         ctx = 0x1bace150
         mail = 0x1bad8fa0
         msgnum = 0
         bit = 464309220
         ret =<value optimized out>
#4  0x00000000004061d1 in cmd_quit (client=0x1bac4a00, name=0x1baccbd4 "", args=0x406a0c 
"") at pop3-commands.c:274
No locals.
#5  client_command_execute (client=0x1bac4a00, name=0x1baccbd4 "", args=0x406a0c 
"") at pop3-commands.c:773
No locals.
#6  0x00000000004045c9 in client_handle_input (client=0x1bac4a00) at 
pop3-client.c:628
         _data_stack_cur_id = 3
         line = 0x1baab872 "QUIT"
         args = 0x406a0c ""
         ret =<value optimized out>
#7  0x00002b4114db0698 in io_loop_call_io (io=0x1bac01d0) at ioloop.c:384
         ioloop = 0x1baa8610
         t_id = 2
#8  0x00002b4114db19d5 in io_loop_handler_run (ioloop=<value optimized out>) at 
ioloop-epoll.c:213
         ctx =<value optimized out>
         event = 0x1baa88b0
         list = 0x1bac0220
         io = 0x0
         tv = {tv_sec = 9, tv_usec = 871818}
         events_count =<value optimized out>
         msecs =<value optimized out>
---Type<return>  to continue, or q<return>  to quit---
         ret = 1
         i = 0
         call = false
#9  0x00002b4114db062d in io_loop_run (ioloop=0x1baa8610) at ioloop.c:405
No locals.
#10 0x00002b4114d9ef13 in master_service_run (service=0x1baa84e0, 
callback=0x1baccbe4) at master-service.c:478
No locals.
#11 0x00000000004039a4 in main (argc=1, argv=0x1baa8370) at main.c:252
         service_flags =<value optimized out>
         storage_service_flags = MAIL_STORAGE_SERVICE_FLAG_DISALLOW_ROOT
         postlogin_socket_path = 0x0
         username = 0x0
         c =<value optimized out>
         set_roots = {0x4072a0, 0x0}
(gdb) quit

I have also kept the user's mailbox. I couldn't reproduce the problem by talking
POP3 directly to the server by hand.

Any ideas?

Thanks,

Kostas

Hi Timo,

indeed it is a bug that I could not reproduce myself.
Having debug symbols and producing the stack trace is the next
logical step and I will work on this tomorrow.
Since --enable-debug does not work in your configure script, can you
direct me as to what is needed? Is there an option in configure or
do I need to mess with the makefiles?

On the other hand, I have found two different bugs.
Having pop3_lock_session=yes we have the situation described here and also
of course delays in local deliveries in case a client has an active pop
session. And I can tell you we have a lot of abusing clients that keep
hitting our pop servers continuously, or keep connections open for a VERY
long time.

To address that, we put pop3_lock_session=no. In this case, there is an
fcntl
lock leak somewhere. The good news is that we have reproduced that and I
will
send relevant information in a different mail.
I also read the following thread, from a while back:

http://www.dovecot.org/list/dovecot/2009-February/037098.html

Regards,

Kostas


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