Re: [PATCH 08/10] NOTIFIER: Take over TIF_MCE_NOTIFY and implementtask return notifier

From: Avi Kivity
Date: Wed Jun 15 2011 - 04:51:42 EST


On 06/14/2011 08:13 PM, Luck, Tony wrote:
>Since we can't have nested #MC (due to the IST mechanism resetting %rsp
>and clobbering the previous invocation's stack), we have to clear MCIP
>outside the #MC handler. And that means irq_work_queue()
>
>(note that this changes the behaviour from memory corruption to shutdown
>state; both suck, but one more than the other).

Hmm. We currently clear MCIP inside the handler (at the very end, but
still inside). Deferring clearing would make sense - but we'd have to
be sure to do so a.s.a.p on all processors. It also would change how
we look at the possibility of a process being able to run and re-execute
an instruction that causes a machine check. If we defer clearing MCIP
this won't just be annoying, it will be fatal (if any cpu hasn't yet
got to the work queue to clear MCIP).

Clearly, the work queue (or thread) has to be real-time at the highest priority.

--
error compiling committee.c: too many arguments to function

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