Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 21 May 2014 15:52:16 -0700 | Subject | Re: [RFC] x86_64: A real proposal for iret-less return to kernel |
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On Wed, May 21, 2014 at 3:48 PM, Borislav Petkov <bp@alien8.de> wrote: > On Wed, May 21, 2014 at 03:39:11PM -0700, Andy Lutomirski wrote: >> But if we get a new MCE in here, it will be an MCE from kernel context >> and it's fatal. So, yes, we'll clobber the stack, but we'll never >> return (unless tolerant is set to something insane), so who cares? > > Ok, but we still have to do the work before returning to the process. So > if not mce_notify_process() how else are you suggesting we do this?
I'm suggesting that you re-enable interrupts and do the work in do_machine_check. I think it'll just work. It might pay to set a flag so that you panic very loudly if do_machine_check recurses.
I suspect that, if the hardware is generating machine checks while doing memory poisoning, the hardware is broken enough that even panicking might not work, though :)
--Andy
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