On Tue, Jun 25, 2013 at 01:21:30PM -0400, Steven Rostedt wrote:
> On Tue, 2013-06-25 at 12:55 -0400, Dave Jones wrote:
>
> > While I've been spinning wheels trying to reproduce that softlockup bug,
> > On another machine I've been refining my list-walk debug patch.
> > I added an ugly "ok, the ringbuffer is playing games with lower two bits"
> > special case.
> >
> > But what the hell is going on here ?
> >
> > next->prev should be prev (ffff88023c6cdd18), but was 00ffff88023c6cdd.
> > (next=ffff880243288001).
> >
> > (trace comes from the same ringbuffer code)
>
> What's the above saying? ffff880243288000->prev == 00ffff88023c6cdd but
> it should have been ffff88023c6cdd18? That is: ffff88023c6cdd18->next ==
> ffff880243288001?
It's saying something has done >>8 on a pointer, and stuck it in a list head.
> Not sure how that would mess up. The ring-buffer code has lots of
> integrity checks to make sure nothing like this breaks.
My integrity checks can beat up your integrity checks.
Dav
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