Messages in this thread | | | Date | Wed, 18 Jan 2012 08:09:57 -0800 | From | Tejun Heo <> | Subject | Re: Kernel crash in icq_free_icq_rcu |
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On Wed, Jan 18, 2012 at 09:20:05AM -0500, Vivek Goyal wrote: > > Not allocating icq if request is never going to go to elevator as elevator > > switch was happening makes sense to me. > > > > I tried this patch. It went little further and crashed at a different > > place. I think this seems to be separate merging issue Tejun is trying > > to track down. > > Applied Tejun's debug patch to return early and not call into elevator > for checking whether merge is allowed or not. Things seems to be stable > now for me.
Yeah, plug merge is calling into elevator code without any synchronization, so it's bound to be broken. Given plugging is per-task, I don't think we really need to query elevator about merging bio's. The request is not on elevator and plugging is part of issuing mechanism, not scheduling, after all. Jens, what do you think?
Thanks.
-- tejun
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