Re: frequent lockups in 3.18rc4

From: Linus Torvalds
Date: Mon Dec 01 2014 - 15:36:40 EST


On Mon, Dec 1, 2014 at 12:28 PM, DÃniel Fraga <fragabr@xxxxxxxxx> wrote:
>
> Hi Paul. Please, I'd like the patch, because without
> preemption, I'm unable to trigger this bug.

Ok, that's already interesting information. And yes, it would probably
be interesting to see if CONFIG_PREEMPT=y but !CONFIG_TREE_PREEMPT_RCU
then solves it too, to narrow it down to one but not the other..

DaveJ - what about your situation? The standard Fedora kernels use
CONFIG_PREEMPT_VOLUNTARY, do you have CONFIG_PREEMPT and
CONFIG_TREE_PREEMPT_RCU enabled? I think you and Sasha both saw some
RCU oddities too, no?

Linus
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