[PATCH 5.14 394/432] ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()

Greg Kroah-Hartman
2021-09-16T17:47:21Z

From: chenying <chenying.kernel@bytedance.com>

commit 52d5a0c6bd8a89f460243ed937856354f8f253a3 upstream.

If function ovl_instantiate() returns an error, ovl_cleanup will be called
and try to remove newdentry from wdir, but the newdentry has been moved to
udir at this time. This will causes BUG_ON(victim->d_parent->d_inode !=
dir) in fs/namei.c:may_delete.

Signed-off-by: chenying <chenying.kernel@bytedance.com>
Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly created inode")
Link: https://lore.kernel.org/linux-unionfs/e6496a94-a161-dc04-c38a-d2544633acb4@bytedance.com/
Cc: <stable@vger.kernel.org> # v4.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/overlayfs/dir.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -542,8 +542,10 @@ static int ovl_create_over_whiteout(stru
goto out_cleanup;
}
err = ovl_instantiate(dentry, inode, newdentry, hardlink);
- if (err)
- goto out_cleanup;
+ if (err) {
+ ovl_cleanup(udir, newdentry);
+ dput(newdentry);
+ }
out_dput:
dput(upper);