[V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context

Peter Zijlstra peterz at infradead.org
Thu Aug 20 16:18:16 PDT 2015

On Thu, Aug 06, 2015 at 02:45:43PM +0900, Hidehiro Kawai wrote:
> When cpu-A panics on NMI just after cpu-B has panicked, cpu-A loops
> infinitely in NMI context.  Especially for x86, cpu-B issues NMI IPI
> to other cpus to save their register states and do some cleanups if
> kdump is enabled, but cpu-A can't handle the NMI and fails to save
> register states.
> To solve thie issue, we wait for the timing of the NMI IPI, then
> call the NMI handler which saves register states.

Sorry, I don't follow, what?

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