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To: Robert Watson <rwatson@freebsd.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Fri, 15 Aug 2003 23:01:50 EDT."
             <Pine.NEB.3.96L.1030815225914.97011A-100000@fledge.watson.org> 
Date: Sat, 16 Aug 2003 09:12:27 +0200
Message-ID: <18472.1061017947@critter.freebsd.dk>
cc: current@freebsd.org
cc: Kris Kennaway <kris@obsecurity.org>
Subject: Re: LOR with filedesc structure and Giant 
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In message <Pine.NEB.3.96L.1030815225914.97011A-100000@fledge.watson.org>, Robe
rt Watson writes:
>
>On Fri, 15 Aug 2003, Kris Kennaway wrote:
>
>> The problem seems to be due to select() being called on the /dev/null
>> device, and it is holding the filedesc lock when it reaches
>> PICKUP_GIANT() in spec_poll.
>
>Yeah, this is pretty much the same issue you've been bumping into for a
>bit -- we hold filedesc lock over select(), which means every object we
>poll can't grab a lock that either comes before the file descriptor lockin
>the lock order, or that might sleep.

Doesn't this effectively doom any attempt at getting rid af Giant
from below ?

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.