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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, Yunjian Wang <wangyunjian@huawei.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.11 166/329] SUNRPC: Fix null pointer dereference in svc_rqst_free()
Date:   Mon, 17 May 2021 16:01:17 +0200
Message-Id: <20210517140307.753790459@linuxfoundation.org>
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From: Yunjian Wang <wangyunjian@huawei.com>

[ Upstream commit b9f83ffaa0c096b4c832a43964fe6bff3acffe10 ]

When alloc_pages_node() returns null in svc_rqst_alloc(), the
null rq_scratch_page pointer will be dereferenced when calling
put_page() in svc_rqst_free(). Fix it by adding a null check.

Addresses-Coverity: ("Dereference after null check")
Fixes: 5191955d6fc6 ("SUNRPC: Prepare for xdr_stream-style decoding on the server-side")
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/svc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 7034b4755fa1..16b6681a97ab 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -846,7 +846,8 @@ void
 svc_rqst_free(struct svc_rqst *rqstp)
 {
 	svc_release_buffer(rqstp);
-	put_page(rqstp->rq_scratch_page);
+	if (rqstp->rq_scratch_page)
+		put_page(rqstp->rq_scratch_page);
 	kfree(rqstp->rq_resp);
 	kfree(rqstp->rq_argp);
 	kfree(rqstp->rq_auth_data);
-- 
2.30.2