followup: stuck lmtpd processes

[John Wade]

Hi Andrew,

I was the one who wrote the message you found.   I finally came to the 
conclusion that the flat file locking mechanism is somewhat broken in 
Cyrus, but I was never a good enough C programmer to pin down what was 
happening.  (The mmap stuff makes it really tricky to debug.)    I 
wanted to blame it on the Linux kernel, but I know that others have 
experienced the same problems in Solaris.

I finally gave up and wrote a locking timeout patch for 2.0.16.   see 
http://www.oakton.edu/~jwade/cyrus/ for the patch and full details

A number of other folks have tried this patch successfully on 2.0.16 and 
2.1.x, and I know it has resolved our problem.

If you can solve the particular bug that causes this, more power to you, 
if not, my work around resolves a number of possible deadlock issues.

Enjoy,
John



Andrew Morgan wrote:

>Following up on my previous post about stuck lmtpd processes.  I found
>this incredibly detailed faq at:
>
>http://www.faqchest.com/prgm/cyrus-l/cyrus-01/cyrus-0111/cyrus-011102/cyrus01111023_33254.html
>
>This isn't exactly the same problem, but the steps on that page helped me
>figure out that they are all stuck trying to get a lock on:
>
>/private/cyrus/mail/k/user/krolickp/cyrus.header
>
>Looking at /proc/locks shows:
>
>7: POSIX  ADVISORY  WRITE 21903 08:11:42107658 0 EOF d23895e0 c3217f44 c510e4c4 00000000 ccbf076c
>7: -> POSIX  ADVISORY  WRITE 32485 08:11:42107658 0 EOF ccbf0760 ee36ac44 f3bb26a4 d23895e0 ee36ac4c
>7: -> POSIX  ADVISORY  WRITE 1802 08:11:42107658 0 EOF ee36ac40 c050ea04 ccbf0764 d23895e0 c050ea0c
>7: -> POSIX  ADVISORY  WRITE 1217 08:11:42107658 0 EOF c050ea00 ee36a344 ee36ac44 d23895e0 ee36a34c
>...
>
>
>I don't see how this deadlock occurred, but I'm willing to help debug it.
>
>	Andy
>
>
>
>  
>