6.1RC system nearly freezing

Robert Watson rwatson at FreeBSD.org
Mon Apr 24 13:26:30 UTC 2006

On Thu, 20 Apr 2006, Henri Hennebert wrote:

> I upgrade a web, squid, mail server (under SMP with 2 pentium III) to 6.1-RC 
> (Apr 9 2006) and encounter 2 `freezing'.
> The system is still responding to http requests but I can't login on the 
> console or through ssh -- no shell prompt. No more mail delivery.
> I break to KDB and found more then 1000 sendmail processes waiting for 
> devfs...
> call boot(0) can't complete the shutdown process.
> I join the KDB informations. Let me know if more informations are needed.

Are you running with WITNESS and INVARIANTS enabled?  If not, could you do so 
and see if the problem is reproduceable, and if so, whether or not WITNESS 
(and friends) generate any warnings?

It looks like something has leaked a lock, resulting in deadlock.  The 
question is, however, which lock, and where.  WITNESS may be able to provide 
some insight into this; if you could run "show alllocks" with WITNESS in 
place, that would be helpful also.

Robert N M Watson

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