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From:   Xiyu Yang <xiyuyang19@fudan.edu.cn>
To:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        "J. Bruce Fields" <bfields@fieldses.org>,
        Chuck Lever <chuck.lever@oracle.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, linux-nfs@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     yuanxzhang@fudan.edu.cn, Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Xin Xiong <xiongx18@fudan.edu.cn>,
        Xin Tan <tanxin.ctf@gmail.com>
Subject: [PATCH] net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change
Date:   Thu,  9 Sep 2021 12:32:38 +0800
Message-Id: <1631161958-77832-1-git-send-email-xiyuyang19@fudan.edu.cn>
Precedence: bulk

The refcount leak issues take place in an error handling path. When the
3rd argument buf doesn't match with "offline", "online" or "remove", the
function simply returns -EINVAL and forgets to decrease the reference
count of a rpc_xprt object and a rpc_xprt_switch object increased by
rpc_sysfs_xprt_kobj_get_xprt() and
rpc_sysfs_xprt_kobj_get_xprt_switch(), causing reference count leaks of
both unused objects.

Fix this issue by jumping to the error handling path labelled with
out_put when buf matches none of "offline", "online" or "remove".

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
---
 net/sunrpc/sysfs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
index 64da3bfd28e6..0cce0375107f 100644
--- a/net/sunrpc/sysfs.c
+++ b/net/sunrpc/sysfs.c
@@ -265,8 +265,10 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
 		online = 1;
 	else if (!strncmp(buf, "remove", 6))
 		remove = 1;
-	else
-		return -EINVAL;
+	else {
+		count = -EINVAL;
+		goto out_put;
+	}
 
 	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE)) {
 		count = -EINTR;
-- 
2.7.4