linux-kernel - [PATCH 5.6 080/166] NFS: direct.c: Fix memory leak of dreq when nfs_get_lock

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Message-Id: <20200422095057.385114082@linuxfoundation.org>
Date:   Wed, 22 Apr 2020 11:56:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Misono Tomohiro <misono.tomohiro@...fujitsu.com>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.6 080/166] NFS: direct.c: Fix memory leak of dreq when nfs_get_lock_context fails

From: Misono Tomohiro <misono.tomohiro@...fujitsu.com>

[ Upstream commit 8605cf0e852af3b2c771c18417499dc4ceed03d5 ]

When dreq is allocated by nfs_direct_req_alloc(), dreq->kref is
initialized to 2. Therefore we need to call nfs_direct_req_release()
twice to release the allocated dreq. Usually it is called in
nfs_file_direct_{read, write}() and nfs_direct_complete().

However, current code only calls nfs_direct_req_relese() once if
nfs_get_lock_context() fails in nfs_file_direct_{read, write}().
So, that case would result in memory leak.

Fix this by adding the missing call.

Signed-off-by: Misono Tomohiro <misono.tomohiro@...fujitsu.com>
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/nfs/direct.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index b768a0b42e82e..ade2435551c89 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -571,6 +571,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter)
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
 		result = PTR_ERR(l_ctx);
+		nfs_direct_req_release(dreq);
 		goto out_release;
 	}
 	dreq->l_ctx = l_ctx;
@@ -990,6 +991,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
 	l_ctx = nfs_get_lock_context(dreq->ctx);
 	if (IS_ERR(l_ctx)) {
 		result = PTR_ERR(l_ctx);
+		nfs_direct_req_release(dreq);
 		goto out_release;
 	}
 	dreq->l_ctx = l_ctx;
-- 
2.20.1