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Message-ID: <21d7e9970812091643n7e3e4fe5g8e44030adfbababa@mail.gmail.com>
Date: Wed, 10 Dec 2008 10:43:07 +1000
From: "Dave Airlie" <airlied@gmail.com>
To: "Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: [patch 021/104] lib/idr.c: fix rcu related race with idr_find
Cc: "Greg KH" <gregkh@suse.de>, linux-kernel@vger.kernel.org,
       stable@kernel.org, "Justin Forbes" <jmforbes@linuxtx.org>,
       "Zwane Mwaikambo" <zwane@arm.linux.org.uk>,
       "Theodore Ts'o" <tytso@mit.edu>, "Randy Dunlap" <rdunlap@xenotime.net>,
       "Dave Jones" <davej@redhat.com>,
       "Chuck Wolber" <chuckw@quantumlinux.com>,
       "Chris Wedgwood" <reviews@ml.cw.f00f.org>,
       "Michael Krufky" <mkrufky@linuxtv.org>,
       "Chuck Ebbert" <cebbert@redhat.com>,
       "Domenico Andreoli" <cavokz@gmail.com>, "Willy Tarreau" <w@1wt.eu>,
       "Rodrigo Rubira Branco" <rbranco@la.checkpoint.com>,
       "Jake Edge" <jake@lwn.net>, "Eugene Teo" <eteo@redhat.com>,
       akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk,
       "Manfred Spraul" <manfred@colorfullife.com>,
       "Clement Calmels" <cboulte@gmail.com>,
       "Nadia Derbey" <Nadia.Derbey@bull.net>,
       "Pierre Peiffer" <peifferp@gmail.com>
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On Wed, Dec 10, 2008 at 8:47 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
>
> On Wed, 10 Dec 2008, Dave Airlie wrote:
>>
>> On Thu, Dec 4, 2008 at 5:49 AM, Greg KH <gregkh@suse.de> wrote:
>> > 2.6.27-stable review patch.  If anyone has any objections, please let us know.
>> >
>> Revert.
>>
>> This caused problems in the F10 kernel with idr, the drm device alloc
>> went all wierd,
>> it might be a drm bug but changing this code triggers it and so it
>> isn't really "stable"
>
> Well, maybe it should be reverted in mainlne too, then?

It appears idr_replace is broken at least in stable with this patch.

I'm trying to track down where the problem is (idr_replace doesn't look like
idr_find in a lot of places and I wonder if this has ever been tested.)

Dave.
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