Re: [PATCH v4 04/10] x86/xsaves: Introduce a new check that allows correct xstates copy from kernel to user directly

From: Dave Hansen
Date: Mon May 02 2016 - 12:06:54 EST

On 05/02/2016 08:57 AM, Yu-cheng Yu wrote:
> On Fri, Apr 29, 2016 at 05:36:48PM -0700, Dave Hansen wrote:
>> If may_copy_fpregs_to_sigframe() were called from a slightly different
>> context, or if we change the call-site, what breaks?
>> In other words. if we can still "may_copy_fpregs_to_sigframe()" no
>> matter the state of fpu.fpstate_active, then I don't think we should be
>> checking it in may_copy_fpregs_to_sigframe().
> Do you mean, don't check fpu.fpstate_active here?

Not really. I'm asking *why* the check is there.