| Message ID | 20211124062452.2343575-1-yangerkun@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] hugetlbfs: avoid overflow in hugetlbfs_fallocate | expand |
On 11/23/21 22:24, yangerkun wrote: > 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-send-email-luojiajun3@huawei.com/ > > Signed-off-by: yangerkun <yangerkun@huawei.com> > --- > fs/hugetlbfs/inode.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Thank you for fixing! Matthew, thanks for DIV_ROUND_UP_ULL! I did not know that existed. Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 49d2e686be74..92ac056e8011 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -651,7 +651,7 @@ 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);
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-send-email-luojiajun3@huawei.com/ Signed-off-by: yangerkun <yangerkun@huawei.com> --- fs/hugetlbfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)