Re: [PATCH] genirq: Set the irq thread policy without checking CAP_SYS_NICE

[Ivo Sieben]

Patch looks OK to me.. but I'm not an expert.

Regards,
Ivo Sieben

2013/10/11 Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>:
> From: Thomas Pfaff <tpfaff@xxxxxxx>
>
> In commit ee23871389 ("genirq: Set irq thread to RT priority on
> creation") we moved the assigment of the thread's priority from the
> thread's function into __setup_irq(). That function may run in user
> context for instance if the user opens an UART node and then driver
> calls requests in the ->open() callback. That user may not have
> CAP_SYS_NICE and so the irq thread won't run with the SCHED_OTHER
> policy.
>
> This patch uses sched_setscheduler_nocheck() so we omit the CAP_SYS_NICE
> check which is otherwise required for the SCHED_OTHER policy.
>
> Cc: Ivo Sieben <meltedpianoman@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Thomas Pfaff <tpfaff@xxxxxxx>
> [bigeasy: rewrite the changelog]
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>  kernel/irq/manage.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 514bcfd..3e59f95 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -956,7 +956,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
>                         goto out_mput;
>                 }
>
> -               sched_setscheduler(t, SCHED_FIFO, &param);
> +               sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
>
>                 /*
>                  * We keep the reference to the task struct even if
> --
> 1.8.4.rc3
>
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