[PATCH 5.3 020/105] cgroup: dont put ERR_PTR() into fc->root

Greg Kroah-Hartman
2019-12-11T15:11:56Z

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit 630faf81b3e61bcc90dc6d8b497800657d2752a5 ]

the caller of ->get_tree() expects NULL left there on error...

Reported-by: Thibaut Sautereau <thibaut@sautereau.fr>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/cgroup/cgroup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 8be1da1ebd9a4..f23862fa15146 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2119,11 +2119,12 @@ int cgroup_do_get_tree(struct fs_context *fc)

nsdentry = kernfs_node_dentry(cgrp->kn, sb);
dput(fc->root);
- fc->root = nsdentry;
if (IS_ERR(nsdentry)) {
- ret = PTR_ERR(nsdentry);
deactivate_locked_super(sb);
+ ret = PTR_ERR(nsdentry);
+ nsdentry = NULL;
}
+ fc->root = nsdentry;
}

if (!ctx->kfc.new_sb_created)
--
2.20.1