[Dovecot] imap failed asssert in imap-bodystructure.c

[Matt Ronge]

I'm running Dovecot on a Debian system which recently has been  
failing on an assert(). I have a spam mailbox that if I try and open  
(from any client), the imap process dies and this is written to the  
error logs:

Dec 21 18:57:11 theronge imap(mronge): file imap-bodystructure.c:  
line 278 (part_parse_headers): assertion failed: (part->physical_pos  
 >= input->v_offset - start_offset)
Dec 21 18:57:11 theronge dovecot: child 28911 (imap) killed with  
signal 6

I had this same issue with my Inbox a few weeks ago, so I moved all  
the e-mail out and moved each piece back in one by one, in order to  
determine if a piece of mail was causing the issue. As soon as all my  
mail was moved back in, the issue went away and I was able to load my  
Inbox as usual. I still have the same issue with my spam mailbox, is  
there anything particular I can do to help debug this issue? In the  
past I've rm'ed all the mail in my spam mailbox and that fixes it.

One thing that may be related is that I only noticed this issue after  
I had setup Spambayes, which does it's work via procmail. The  
mailboxes that I've had the issue with, all had headers that contain  
a Spambayes header, usually like so:

X-Spam-Score: 26
X-Spam-Score: 0.6 (/)
Sender: mailman-bounces at acm.uiuc.edu
Errors-To: mailman-bounces at acm.uiuc.edu
X-Spam-Score: 0.1 (/)
X-Authenticated-Sender:
X-Spam-Details: rule=cautious-plus_notspam policy=cautious-plus score=26
         mlx=26 adultscore=0 adjust=0 reason=mlx engine=3.1.0-0611300000
         definitions=main-0612060023
X-Spam-OrigSender: mailman-bounces at acm.uiuc.edu
X-Spam-Bar: ***
X-Spambayes-Classification: spam; 1.00
X-Spambayes-Trained: spam

I'm not sure if it's related, but it's a shock in the dark on my  
part. Any suggested steps that might help isolate this bug?
--
Matt Ronge