Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!

[Borislav Petkov]

On Wed, Nov 30, 2016 at 09:54:58AM +0100, Thomas Gleixner wrote:
> Right, that's the safe bet. But I'm quite sure that the C1E crap only
> starts to work _after_ ACPI initialization.

Yap, I think it is an ACPI decision whether to enter C1E or not. And all
those boxes which are unaffected - they actually are but since the FW
doesn't enter C1E, they don't hit the bug.

> tick_force_broadcast() is irreversible

So if I let the cores in that small window use amd_e400_idle() and
then when I detect the machine doesn't enter C1E after all, I do
tick_broadcast_exit() on all cores in amd_e400_c1e_mask, then clear it
and free it, that would work?

Or do you see a better solution?

Thanks.

-- 
Regards/Gruss,
    Boris.

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