From b2e3a39982886b72c8511fe6af8ecd794dfbc6a5 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@gmail.com>
Date: Fri, 6 Dec 2019 08:33:36 +0200
Subject: [PATCH 3/6] ovl: relax WARN_ON() on rename to self
References: bsc#1189846
Patch-mainline: v5.5-rc2
Git-commit: 6889ee5a53b8d969aa542047f5ac8acdc0e79a91
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>
Acked-by: David Disseldorp <ddiss@suse.de>
---
fs/overlayfs/dir.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 15c703cfe22a..bffd8a8f46dc 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1035,7 +1035,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
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;
--
2.32.0