Re: [PATCH 17/21] MSI: Clear the irq_desc's msi pointer on free

From: Michael Ellerman
Date: Thu Mar 22 2007 - 19:02:10 EST


On Thu, 2007-03-22 at 08:23 -0600, Eric W. Biederman wrote:
> Michael Ellerman <michael@xxxxxxxxxxxxxx> writes:
>
> > Currently we never clear the msi_desc pointer in the irq_desc. This
> > leaves us with a pointer to free'ed memory hanging around. No one seems
> > to have hit this, so presumably other parts of the code are protecting
> > us from ever using the stale pointer .. or we're just lucky, we should
> > still clear it.
>
> Hmm. Maybe. Currently this is done in dynamic_irq_cleanup,
> at least for everything except sparc64.

OK, I missed that. I still think we should do it here, otherwise there's
a window, however small, where the msi_desc pointer is pointing at freed
memory.

cheers

--
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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