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Date: Tue, 25 Nov 2014 09:22:04 -0800
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Subject: Re: frequent lockups in 3.18rc4
From: Linus Torvalds <torvalds@linux-foundation.org>
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        Frederic Weisbecker <fweisbec@gmail.com>,
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On Mon, Nov 24, 2014 at 9:36 PM, Jürgen Groß <jgross@suse.com> wrote:
>
> Funny, during testing some patches related to Xen I hit the lockup
> issue. It looked a little bit different, but a variation of your patch
> solved my problem.
>
> I could reproduce the issue within a few minutes reliably without the
> patch below. With it the machine survived 12 hours and is still running.

Do you have a backtrace for the failure case? I have no problem
applying this part of the patch (I really don't understand why x86-64
hadn't gotten the proper code from 32-bit), but I'd like to see (and
document) where the fault happens for this.

Since you can apparently reproduce this fairly easily with a broken
kernel, getting a backtrace shouldn't be too hard?

                     Linus