[RFC PATCH] Fix Oops in rtas_stop_self()
David.Laight at ACULAB.COM
Mon Apr 28 19:06:36 EST 2014
From: Li Zhong
> On Fri, 2014-04-25 at 22:18 +1000, Anton Blanchard wrote:
> > Hi,
> > > When trying offline cpus, I noticed following Oops in
> > > rtas_stop_self(), and it seems caused by commit 41dd03a9. The Oops
> > > disappears after reverting this commit.
> > >
> > > After reading the code, I guess it might be caused by moving the
> > > rtas_args to stack. Still need some more time to read enter_rtas to
> > > understand why it happens, but the problem seems could be solved by
> > > moving the rtas_args away from stack by adding static before it.
> > Nice catch. RTAS is 32bit and if your box has more than 4GB RAM then
> > your stack could easily be outside 32bit range.
> Ah, yes, the stack here is obviously at a much higher address than 4GB.
Are we talking of physical or virtual addresses here?
(or even user?)
Is there a re-entrancy problem using kernel static data?
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