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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xin Xiong <xiongx18@fudan.edu.cn>,
        Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Xin Tan <tanxin.ctf@gmail.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 126/285] NFSv4.2: fix reference count leaks in _nfs42_proc_copy_notify()
Date:   Tue, 12 Apr 2022 08:29:43 +0200
Message-Id: <20220412062947.303168261@linuxfoundation.org>
In-Reply-To: <20220412062943.670770901@linuxfoundation.org>
References: <20220412062943.670770901@linuxfoundation.org>
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From: Xin Xiong <xiongx18@fudan.edu.cn>

[ Upstream commit b7f114edd54326f730a754547e7cfb197b5bc132 ]

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The reference counting issue happens in two error paths in the
function _nfs42_proc_copy_notify(). In both error paths, the function
simply returns the error code and forgets to balance the refcount of
object `ctx`, bumped by get_nfs_open_context() earlier, which may
cause refcount leaks.

Fix it by balancing refcount of the `ctx` object before the function
returns in both error paths.

Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nfs/nfs42proc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index 8b21ff1be717..438de4f93ce7 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -592,8 +592,10 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,
 
 	ctx = get_nfs_open_context(nfs_file_open_context(src));
 	l_ctx = nfs_get_lock_context(ctx);
-	if (IS_ERR(l_ctx))
-		return PTR_ERR(l_ctx);
+	if (IS_ERR(l_ctx)) {
+		status = PTR_ERR(l_ctx);
+		goto out;
+	}
 
 	status = nfs4_set_rw_stateid(&args->cna_src_stateid, ctx, l_ctx,
 				     FMODE_READ);
@@ -601,7 +603,7 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,
 	if (status) {
 		if (status == -EAGAIN)
 			status = -NFS4ERR_BAD_STATEID;
-		return status;
+		goto out;
 	}
 
 	status = nfs4_call_sync(src_server->client, src_server, &msg,
@@ -610,6 +612,7 @@ static int _nfs42_proc_copy_notify(struct file *src, struct file *dst,
 	if (status == -ENOTSUPP)
 		src_server->caps &= ~NFS_CAP_COPY_NOTIFY;
 
+out:
 	put_nfs_open_context(nfs_file_open_context(src));
 	return status;
 }
-- 
2.35.1