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

[Valentin Schneider]

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.