Merge branch 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/ke…

…rnel/git/viro/vfs Pull vfs fix from Al Viro: "Braino fix for iov_iter_revert() misuse" * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fix braino in generic_file_read_iter()
zarubaf · May 9, 2017 · 339fbf6 · 339fbf6
2 parents 8ee74a9 + 5b47d59
commit 339fbf6
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diff --git a/lib/iov_iter.c b/lib/iov_iter.c
@@ -790,6 +790,8 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
 {
 	if (!unroll)
 		return;
+	if (WARN_ON(unroll > MAX_RW_COUNT))
+		return;
 	i->count += unroll;
 	if (unlikely(i->type & ITER_PIPE)) {
 		struct pipe_inode_info *pipe = i->pipe;

diff --git a/mm/filemap.c b/mm/filemap.c
@@ -2050,7 +2050,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 			iocb->ki_pos += retval;
 			count -= retval;
 		}
-		iov_iter_revert(iter, iov_iter_count(iter) - count);
+		iov_iter_revert(iter, count - iov_iter_count(iter));
 
 		/*
 		 * Btrfs can have a short DIO read if we encounter