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

[H. Peter Anvin]

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.

	-hpa