VFS: move BUG_ON test for symlink nd->depth after current->link_count test
This solves a serious VFS-level bug in nested_symlink (which was rewritten from
do_follow_link), and follows the order of depth tests that existed before.
The bug triggers a BUG_ON in fs/namei.c:1381, when running racer with
symlink and rename ops.
Signed-off-by: Erez Zadok <ezk@xxxxxxxxxxxxx>
Acked-by: Miklos Szeredi <mszeredi@xxxxxxx>
CC: stable@xxxxxxxxxx
diff --git a/fs/namei.c b/fs/namei.c
index 017c3fa..7a93387 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1343,12 +1343,12 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
{
int res;
- BUG_ON(nd->depth >= MAX_NESTED_LINKS);
if (unlikely(current->link_count >= MAX_NESTED_LINKS)) {
path_put_conditional(path, nd);
path_put(&nd->path);
return -ELOOP;
}
+ BUG_ON(nd->depth >= MAX_NESTED_LINKS);
nd->depth++;
current->link_count++;
--
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