Hi Konstantin, Xunlei, 2016-07-11 16:42 GMT+08:00 Xunlei Pang <xpang@xxxxxxxxxx>: > On 2016/07/11 at 16:22, Xunlei Pang wrote: >> On 2016/07/11 at 15:25, Wanpeng Li wrote: >>> 2016-06-16 20:57 GMT+08:00 Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>: >>>> 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: > > s/NULL/empty-entity cfs_rq se/ > >> pick_next_entity(): >> if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) ^^^^^^^^^^^^^ I think this will return false. Regards, Wanpeng Li -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html