Hi Mathieu, On 13/02/18 13:32, Mathieu Poirier wrote: > No synchronisation mechanism exist between the cpuset subsystem and calls > to function __sched_setscheduler(). As such it is possible that new root > domains are created on the cpuset side while a deadline acceptance test > is carried out in __sched_setscheduler(), leading to a potential oversell > of CPU bandwidth. > > By making available the cpuset_mutex to the core scheduler it is possible > to prevent situations such as the one described above from happening. > > Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> > --- [...] > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index f727c3d0064c..0d8badcf1f0f 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4176,6 +4176,13 @@ static int __sched_setscheduler(struct task_struct *p, > } > > /* > + * Make sure we don't race with the cpuset subsystem where root > + * domains can be rebuilt or modified while operations like DL > + * admission checks are carried out. > + */ > + cpuset_lock(); > + > + /* Mmm, I'm afraid we can't do this. __sched_setscheduler might be called from interrupt contex by normalize_rt_tasks(). Best, - Juri -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
