Re: [PATCH 01/16] x86, fpu: wrap get_xsave_addr() to make it safer

[Borislav Petkov]

On Wed, Apr 22, 2015 at 05:32:45PM +0200, Oleg Nesterov wrote:
> How? I am certainly missing you point... OK, please forge about FPU.
> Consider this code:
> 
> 	tsk = current;
> 	for (;;)
> 		BUG_ON(tsk != current);
> 
> it doesn't need to disable preemption. We do not care if CPU switches
> to another thread, even if this thread executes the same code. Because
> its tsk/current will differ, but "tsk == current" will be still true.
> 
> Could you please spell?

Bah, forget what I said. tglx schooled me on IRC. We always do get
called with tsk == current. Sorry for the confusion...

> See above... used_math() should be correct because we know that tsk==current,
> but I agree that tsk_used_math(tsk) looks better.

Right, and it is clear what's going on, even to lusers like me.

Thanks for teaching me guys.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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