[dovecot] Three *very* strange bugs
- Attached is a mbox file that triggers Bug #1 and #2.
- Go here if you want to test dovecot for RH9: https://bugzilla.fedora.us/show_bug.cgi?id=160
- If somebody has a different IMAP server than dovecot, could you please test how Evolution reacts to reading this message?
Bug #1 dovecot and #2 evolution-1.2.3
I am using dovecot-0.99.9-test3 on RH9, reading mail with evolution-1.2.2-5 on RH9. Whenever I attempt to view this one particular spam message, evolution pops up an error like:
Error while 'Retrieving message 4': Server unexpectedly disconnected: No such file or directory
Simultaneously this appears in my /var/log/maillog: Apr 15 01:44:50 server dovecot: child 20328 (imap) killed with signal 11
If I attempt to keep reading mail, it logs in again to dovecot and works normally until I attempt to read that spam again. Evolution displays the error popup again though I don't see another signal 11 in maillog. After this point I am unable to log back into dovecot without restarting the daemon.
Here's the strange part... I browsed the same IMAP folder from KMail, and kmail has no problem reading that spam message. dovecot's [imap] process does not segmentation fault.
Does this mean an evolution bug when reading this particular spam exposed a dovecot segmentation fault?
Bug #3 kernel?
This is an unrelated bug and perhaps not the fault of dovecot. When I attempted to use strace to get some debugging info on the [imap] process, this happened:
[root@server /]# strace -p 20486 trace: ptrace(PTRACE_SYSCALL, ...): Operation not permitted detach: ptrace(PTRACE_DETACH, ...): Operation not permitted [root@server /]#
This isn't normal right? After doing this, dovecot stops working and I need to restart the daemon in order to establish new connections. That [imap] process becomes unkillable, even kill -9 wont work. Unkillable process usually means kernel bug, right?
warren 20345 1 7 01:46 ? 00:00:34 [imap]
This is kernel-2.4.20-9 in Red Hat Linux 9. Is dovecot exposing a Red Hat kernel bug when I try to strace that process, or is strace supposed to fail, the dovecot daemon ceases to function and [imap] process becomes completely unkillable? =)
Warren Togami warren@togami.com
On Tue, 2003-04-15 at 15:43, Warren Togami wrote:
Simultaneously this appears in my /var/log/maillog: Apr 15 01:44:50 server dovecot: child 20328 (imap) killed with signal 11
If I attempt to keep reading mail, it logs in again to dovecot and works normally until I attempt to read that spam again. Evolution displays the error popup again though I don't see another signal 11 in maillog. After this point I am unable to log back into dovecot without restarting the daemon.
OK, thanks, fixed. Dovecot crashed with "FETCH nnn BODY[n.MIME]", so pretty much any multipart mail crashed with Evolution.
Here's the strange part... I browsed the same IMAP folder from KMail, and kmail has no problem reading that spam message. dovecot's [imap] process does not segmentation fault.
KMail doesn't fetch MIME headers separately. I think it fetches whole message at once.
Bug #3 kernel?
This is an unrelated bug and perhaps not the fault of dovecot. When I attempted to use strace to get some debugging info on the [imap] process, this happened:
[root@server /]# strace -p 20486 trace: ptrace(PTRACE_SYSCALL, ...): Operation not permitted detach: ptrace(PTRACE_DETACH, ...): Operation not permitted [root@server /]#
I have no problem stracing. I don't think Dovecot does anything that should prevent it. Or, well, it might be because it's thought of as setuid process, but root should be able to strace it.
participants (2)
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Timo Sirainen
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Warren Togami