Messages in this thread | | | Date | Thu, 20 Nov 2014 18:39:20 -0500 | From | Tejun Heo <> | Subject | Re: frequent lockups in 3.18rc4 |
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On Thu, Nov 20, 2014 at 03:08:03PM -0800, Andy Lutomirski wrote: > > So, for now, all we need is adding nmi check in percpu accessors, > > right? > > > > What's the issue with nmi? Page faults are supposed to nest correctly > inside nmi, right?
Thought they couldn't. Looking at the trace that Frederic linked, it looks like straight-out tracing function recursion due to an unexpected fault while holding a lock. I don't think this can be annotated from percpu accessor side. There's nothing special about the context. :(
Does this matter for anybody other than tracers? Ultimately, the solution would be removing the vmalloc area faulting as Thomas suggested.
Thanks.
-- tejun
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