6.2-STABLE deadlock?

[LI Xin]

Kostik Belousov wrote:
> On Mon, Apr 23, 2007 at 03:56:32AM +0100, Adrian Wontroba wrote:
>> On Tue, Mar 13, 2007 at 02:08:48PM +0000, Adrian Wontroba wrote:
>>> At work, amoungst my stable of old computers running FreeBSD, I have a
>>> Fujitsu M800 - a 4 Zeon SMP processor with 4 GB of memory. This
>>> primarily runs Nagios and a small and lightly used MySQL database, along
>>> with a few inbound FTP transfers per minute. It has a Mylex card based
>>> disc subsystem, ruling out crash dumps.
>>>
>>> At some point during 5.5-STABLE this machine started to occasionally hang ...
>> Another 6-STABLE (cvsupped on 27/03/07) example, with diagnostics taken
>> rather sooner after the hang.  Processes with wmesg=ufs feature often in
>> the ps output.
>>
>> http://www.stade.co.uk/crash1/
> 
> I would suspect the mlx controller. There is several processes (for instance,
> 988, 50918) waiting for completion of block read, and processes in the "ufs"
> states are the result of the lock cascade, IMHO.

I'm not very sure if this is specific to one disk controller.  Actually
I got some occasional reports about similar hangs on amd64 6.2-RELEASE
(slightly patched version) that most of processes stuck in the 'ufs'
state, under very light load, the box was equipped with amr(4) RAID.

I was not able to reproduce the problem at my lab, though, it's still
unknown that how to trigger the livelock :-(  Still need some
investigate on their production system.

Cheers,
-- 
Xin LI <delphij at delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!

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