Re: frequent lockups in 3.18rc4

From: Paul E. McKenney
Date: Mon Dec 01 2014 - 18:08:27 EST

On Mon, Dec 01, 2014 at 06:28:31PM -0200, Dâniel Fraga wrote:
> On Mon, 1 Dec 2014 11:14:31 -0800
> "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> > If it would help to have !CONFIG_TREE_PREEMPT_RCU with CONFIG_PREEMPT=y,
> > please let me know and I will create a patch that forces this.
> > (Not mainline material, but if it helps with debug...)
> Hi Paul. Please, I'd like the patch, because without
> preemption, I'm unable to trigger this bug.

Well, this turned out to be way simpler than I expected. Passes
light rcutorture testing. Sometimes you get lucky...

Thanx, Paul

diff --git a/init/Kconfig b/init/Kconfig
index 903505e66d1d..2cf71fcd514f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -469,7 +469,7 @@ choice

config TREE_RCU
bool "Tree-based hierarchical RCU"
- depends on !PREEMPT && SMP
+ depends on SMP
select IRQ_WORK
This option selects the RCU implementation that is

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