From: Amir Goldstein amir73il@gmail.com
commit 6889ee5a53b8d969aa542047f5ac8acdc0e79a91 upstream.
In ovl_rename(), if new upper is hardlinked to old upper underneath overlayfs before upper dirs are locked, user will get an ESTALE error and a WARN_ON will be printed.
Changes to underlying layers while overlayfs is mounted may result in unexpected behavior, but it shouldn't crash the kernel and it shouldn't trigger WARN_ON() either, so relax this WARN_ON().
Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com Fixes: 804032fabb3b ("ovl: don't check rename to self") Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/overlayfs/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -1042,7 +1042,7 @@ static int ovl_rename(struct inode *oldd if (newdentry == trap) goto out_dput;
- if (WARN_ON(olddentry->d_inode == newdentry->d_inode)) + if (olddentry->d_inode == newdentry->d_inode) goto out_dput;
err = 0;