Re: [RFC] x86_64: A real proposal for iret-less return to kernel

[Andy Lutomirski]

On Wed, May 21, 2014 at 2:45 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> Adding Tony.
>
> On 05/21/2014 02:43 PM, Borislav Petkov wrote:
>> On Thu, May 22, 2014 at 06:37:26AM +0900, Linus Torvalds wrote:
>>> Seriously. If an NMI is interrupted by an MCE, you might as well
>>> consider the machine dead. Don't worry about it. We may or may not
>>> recover, but it is *not* our problem.
>>
>> I certainly like this way of handling it. We can even issue a nice
>> banner saying something like "You're f*cked - go change hw."
>>
>
> Actually, it would be a lot better to panic than deadlock (HA systems
> tend to have something in place to catch the panic and/or reboot).  Any
> way we can see if the CPU is already holding that lock and panic in that
> case?
>

Is there anything actually wrong with just panicking if
!user_mode_vm(regs)?  That would make this a lot more sane.

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/