Re: [PATCH 00/11] rcu: Make rcu_core() safe in PREEMPT_RT with NOCB + a few other fixes

[Paul E. McKenney]

On Fri, Oct 08, 2021 at 03:03:02PM +0100, Valentin Schneider wrote:
> On 01/10/21 18:47, Valentin Schneider wrote:
> > On 30/09/21 00:10, Frederic Weisbecker wrote:
> >> PREEMPT_RT has made rcu_core() preemptible, making it unsafe against
> >> concurrent NOCB (de-)offloading.
> >>
> >> Thomas suggested to drop the local_lock() based solution and simply
> >> check the offloaded state while context looks safe but that's not
> >> enough. Here is a bit of rework.
> >>
> >> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> >>       rcu/rt
> >>
> >> HEAD: aac1c58961446c731f2e989bd822ca1fd2659bad
> >>
> >> Thanks,
> >>       Frederic
> >
> > FWIW I've had RCU torture with NOCB toggling running for half a day on my
> > Arm Juno and nothing to report. I still need to rebase this on an -rt tree
> > and give it a spin with CONFIG_PREEMPT_RT.
> 
> Rebased on top of v5.15-rc4-rt7-rebase with Thomas' patch reverted and ran
> the same thing under CONFIG_PREEMPT_RT, nothing seems to catch on fire, so:
> 
> Tested-by: Valentin Schneider <valentin.schneider@xxxxxxx>

Thank you!!!

							Thanx, Paul