From: Chunguang Xu <brookxu@tencent.com> mainline inclusion from mainline-v5.14-rc1 commit d80c228d44640f0b47b57a2ca4afa26ef87e16b0 category: bugfix bugzilla: 187475, https://gitee.com/openeuler/kernel/issues/I5ME0J CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- On the IO submission path, blk_account_io_start() may interrupt the system interruption. When the interruption returns, the value of part->stamp may have been updated by other cores, so the time value collected before the interruption may be less than part-> stamp. So when this happens, we should do nothing to make io_ticks more accurate? For kernels less than 5.0, this may cause io_ticks to become smaller, which in turn may cause abnormal ioutil values. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/1625521646-1069-1-git-send-email-brookxu.cn@gmail.... Signed-off-by: Jens Axboe <axboe@kernel.dk> conflict: block/blk-core.c Signed-off-by: Li Nan <linan122@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-core.c b/block/blk-core.c index 109fb2750453..0b496dabc5ac 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1258,7 +1258,7 @@ void update_io_ticks(struct hd_struct *part, unsigned long now, bool end) unsigned long stamp; again: stamp = READ_ONCE(part->stamp); - if (unlikely(stamp != now)) { + if (unlikely(time_after(now, stamp))) { if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) __part_stat_add(part, io_ticks, end ? now - stamp : 1); } -- 2.20.1