| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 195/267] ovl: relax WARN_ON() on rename to self | Date | Mon, 16 Dec 2019 18:48:41 +0100 |
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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;
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