RE: [PATCH] x86/fpu: XRSTOR is expected to raise #GP

[David Laight]

From: H. Peter Anvin
> Sent: 26 November 2018 19:50
> On 11/26/18 9:49 AM, Sebastian Andrzej Siewior wrote:
> > On 2018-11-26 18:27:06 [+0100], Jann Horn wrote:
> >> commit 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess
> >> fixups") incorrectly replaced the fixup entry for XSTATE_OP with a
> >> user-#PF-only fixup. However, XRSTOR can also raise #GP when the supplied
> >> address points to userspace memory. Change it back.
> >
> > The #GP is raised if the xstate content is invalid. But I guess the
> > details don't matter.
> >
> >> Reported-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> >> Fixes: 75045f77f7a7 ("x86/extable: Introduce _ASM_EXTABLE_UA for uaccess fixups")
> >> Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
> > Acked-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> >
> 
> It does matter -- please correct the patch description, or we might have some
> serious confusion at some arbitrary point in the future with the result that
> the bug gets re-introduced; it would not be the first time.

Better still note it in the code.

	David

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