sched/fair: sanitize vruntime of entity being placed
mainline inclusion from mainline-v6.3-rc4 commit 829c1651 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6TE76 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=829c1651e9c4a6f78398d3e67651cef9bb6b42cc -------------------------------- When a scheduling entity is placed onto cfs_rq, its vruntime is pulled to the base level (around cfs_rq->min_vruntime), so that the entity doesn't gain extra boost when placed backwards. However, if the entity being placed wasn't executed for a long time, its vruntime may get too far behind (e.g. while cfs_rq was executing a low-weight hog), which can inverse the vruntime comparison due to s64 overflow. This results in the entity being placed with its original vruntime way forwards, so that it will effectively never get to the cpu. To prevent that, ignore the vruntime of the entity being placed if it didn't execute for much longer than the characteristic sheduler time scale. [rkagan: formatted, adjusted commit log, comments, cutoff value] Signed-off-by: NZhang Qiao <zhangqiao22@huawei.com> Co-developed-by: NRoman Kagan <rkagan@amazon.de> Signed-off-by: NRoman Kagan <rkagan@amazon.de> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20230130122216.3555094-1-rkagan@amazon.deSigned-off-by: NSongping Yu <yusongping@huawei.com> Reviewed-by: NZhang Qiao <zhangqiao22@huawei.com> Reviewed-by: Nchenhui <judy.chenhui@huawei.com> Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
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