Re: [patch 18/18] sched: Enable smp_processor_id() checks early

Steven Rostedt
2017-05-15T15:13:01Z

On Sun, 14 May 2017 20:27:34 +0200
Thomas Gleixner <tglx@linutronix.de> wrote:

> smp_processor_id() checks are enabled after the boot process is done. That
> hides bugs in the smp bringup and driver initialization code.
>
> Enable it right before the first non-boot CPU is brought up.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> init/main.c | 3 +++
> lib/smp_processor_id.c | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> init/main.c | 3 +++
> lib/smp_processor_id.c | 2 +-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> --- a/init/main.c
> +++ b/init/main.c
> @@ -1025,6 +1025,9 @@ static noinline void __init kernel_init_
> */
> set_cpus_allowed_ptr(current, cpumask_of(raw_smp_processor_id()));
>
> + /* Enable smp_processor_id() checks */
> + system_state = SYSTEM_BOOTING_SMP;
> +

Just a nit, but why set this here and not just before
smp_prepare_cpus()? Anyway...

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve

> cad_pid = task_pid(current);
>
> smp_prepare_cpus(setup_max_cpus);
> --- a/lib/smp_processor_id.c
> +++ b/lib/smp_processor_id.c
> @@ -28,7 +28,7 @@ notrace static unsigned int check_preemp
> /*
> * It is valid to assume CPU-locality during early bootup:
> */
> - if (system_state != SYSTEM_RUNNING)
> + if (system_state < SYSTEM_BOOTING_SMP)
> goto out;
>
> /*
>