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SubjectRe: [PATCH] fb: Rework locking to fix lock ordering on takeover
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On Wed, Nov 21, 2012 at 7:53 AM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> On Wed, 21 Nov 2012 07:45:45 -0500
> Josh Boyer <jwboyer@gmail.com> wrote:
>
>> On Fri, Nov 16, 2012 at 2:27 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> >
>> > [The fb maintainer appears to be absent at the moment].
>> >
>> > This is needed to fix a pile of lockdep splats that now show up because console_lock()
>> > is being properly audited. Hugh Dickins and Sasha Levin have tested it and both reports
>> > all looks good. This is probably not the whole story - the entire fb layer has locking
>> > confusion problems that were previously hidden but it seems to get the ones people hit
>> > in testing. This hopefully explains a few of the weird fb hangs that have been floating
>> > around forever.
>> >
>> > From: Alan Cox <alan@linux.intel.com>
>> >
>> > Adjust the console layer to allow a take over call where the caller already
>> > holds the locks. Make the fb layer lock in order.
>> >
>> > This s partly a band aid, the fb layer is terminally confused about the
>> > locking rules it uses for its notifiers it seems.
>> >
>> > Signed-off-by: Alan Cox <alan@linux.intel.com>
>>
>> Should this eventually get into the stable trees?
>
> Thats a question I'm not sure about at this point. I think the bug is
> real but not caught by the lock checker in older trees but I've not
> investigated.

So... this patch seems to still be twisting in the wind. It should
probably be headed into 3.8 at this point, shouldn't it?

josh


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