On Mon, Nov 23, 2020 at 05:58:42PM +0000, Alex Belits wrote:
> From: Yuri Norov <ynorov@xxxxxxxxxxx>
>
> Make sure that kick_all_cpus_sync() does not call CPUs that are running
> isolated tasks.
>
> Signed-off-by: Yuri Norov <ynorov@xxxxxxxxxxx>
> [abelits@xxxxxxxxxxx: use safe task_isolation_cpumask() implementation]
> Signed-off-by: Alex Belits <abelits@xxxxxxxxxxx>
> ---
> kernel/smp.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 4d17501433be..b2faecf58ed0 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -932,9 +932,21 @@ static void do_nothing(void *unused)
> */
> void kick_all_cpus_sync(void)
> {
> + struct cpumask mask;
> +
> /* Make sure the change is visible before we kick the cpus */
> smp_mb();
> - smp_call_function(do_nothing, NULL, 1);
> +
> + preempt_disable();
> +#ifdef CONFIG_TASK_ISOLATION
> + cpumask_clear(&mask);
> + task_isolation_cpumask(&mask);
> + cpumask_complement(&mask, &mask);
> +#else
> + cpumask_setall(&mask);
> +#endif
> + smp_call_function_many(&mask, do_nothing, NULL, 1);
> + preempt_enable();
Same comment about IPIs here.
> }
> EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
>
> --
> 2.20.1
>
