On 2016/07/11 at 15:25, Wanpeng Li wrote: > 2016-06-16 20:57 GMT+08:00 Konstantin Khlebnikov <khlebni...@yandex-team.ru>: >> Hierarchy could be already throttled at this point. Throttled next >> buddy could trigger null pointer dereference in pick_next_task_fair(). > There is cfs_rq->next check in pick_next_entity(), so how can null > pointer dereference happen?
I guess it's the following code leading to a NULL se returned: pick_next_entity(): if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) se = cfs_rq->next; Regards, Xunlei > Regards, > Wanpeng Li