[dovecot] Three *very* strange bugs

[Warren Togami]

* 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 at server /]# strace -p 20486
trace: ptrace(PTRACE_SYSCALL, ...): Operation not permitted
detach: ptrace(PTRACE_DETACH, ...): Operation not permitted
[root at 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 at togami.com