From: yangerkun yangerkun@huawei.com
hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8JDQ7?from=project-issue
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luojiajun report a problem[1] two years ago which seems still exists in mainline. vfs_fallocate can avoid 'offset + len' trigger overflow, but 'offset + len + hpage_size - 1' may overflow too and will lead to a wrong 'end'. luojiajun give a solution which can fix the wrong 'end' but leave the overflow still happened. Fix it with DIV_ROUND_UP_ULL.
[1] https://patchwork.kernel.org/project/linux-mm/patch/1554775226-67213-1-git-s...
Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Signed-off-by: Zizhi Wo wozizhi@huawei.com --- fs/hugetlbfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 316c4cebd3f3..cb6a5ea74cda 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -836,7 +836,7 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset, * as well as being converted to page offsets. */ start = offset >> hpage_shift; - end = (offset + len + hpage_size - 1) >> hpage_shift; + end = DIV_ROUND_UP_ULL(offset + len, hpage_size);
inode_lock(inode);