[Xenomai] potentially missing timer rating check in select_root_only_timer()

Jan Kiszka jan.kiszka at siemens.com
Wed May 2 07:34:03 CEST 2018


Hi Phong,

On 2018-05-02 03:13, Pham, Phong wrote:
> Hi,
> 
> I am suspecting that in kernel/ipipe/timer.c:select_root_only_timer()
> 
> When t->irq == per_cpu(ipipe_percpu.hrtimer_irq, icpu), a condition to test the timer rating against current timer rating before installing the timer is missing.  That is t->rating > percpu_timer->rating (combined with same irq #) before the condition becomes true.

Conceptually, I-pipe timers should have highest rating. Can you explain
in more details why it should be there?

Also note that your own code looks suspicious: percpu_timer is a per-cpu
variable but is not accesses as such.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux



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