Re: Kernel oops with 2.6.26, padlock and ipsec: probably problem with fpu state changes

Wolfgang Walter
2008-08-08T23:10:55Z

On Friday 08 August 2008, Suresh Siddha wrote:
> On Fri, Aug 08, 2008 at 12:09:46PM -0700, Wolfgang Walter wrote:
> > I don't know though why kernel_fpu_begin exactly fixes the problem:
>
> because it prevents taking a DNA fault inside the kernel (resulting
> in TS_USEDFPU not set).
>
> >
> > Maybe preemption must be disabled when padlocks RNG, ACE, Hash-engine etc.
is
> > used. Maybe just some barrier is needed which preempt_disable provides.
>
> problem can happen even when preemption is disabled.
>
> > What should I do now?
>
> I will post your fix(including the other usages) with the appropriate
changelog
> shortly.
>

Fine.

By the way, if padlock is used from userspace, could this be aproblem, too? I
mean not via the kernel crypto layer but directly. I think these extensions
are not restricted to a privileged user.

Regards,
--
Wolfgang Walter
Studentenwerk München
Anstalt des öffentlichen Rechts
Leiter EDV
Leopoldstraße 15
80802 München
Tel: +49 89 38196-276
Fax: +49 89 38196-144
wolfgang.walter@stwm.de