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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, Colin Ian King <colin.i.king@gmail.com>,
        Alexandra Winter <wintera@linux.ibm.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 05/19] s390/ctcm: fix variable dereferenced before check
Date:   Mon, 16 May 2022 21:36:18 +0200
Message-Id: <20220516193613.657644555@linuxfoundation.org>
In-Reply-To: <20220516193613.497233635@linuxfoundation.org>
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From: Alexandra Winter <wintera@linux.ibm.com>

[ Upstream commit 2c50c6867c85afee6f2b3bcbc50fc9d0083d1343 ]

Found by cppcheck and smatch.
smatch complains about
drivers/s390/net/ctcm_sysfs.c:43 ctcm_buffer_write() warn: variable dereferenced before check 'priv' (see line 42)

Fixes: 3c09e2647b5e ("ctcm: rename READ/WRITE defines to avoid redefinitions")
Reported-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/net/ctcm_sysfs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/net/ctcm_sysfs.c b/drivers/s390/net/ctcm_sysfs.c
index ddb0aa321339..07b7177abf26 100644
--- a/drivers/s390/net/ctcm_sysfs.c
+++ b/drivers/s390/net/ctcm_sysfs.c
@@ -38,11 +38,12 @@ static ssize_t ctcm_buffer_write(struct device *dev,
 	struct ctcm_priv *priv = dev_get_drvdata(dev);
 	int rc;
 
-	ndev = priv->channel[CTCM_READ]->netdev;
-	if (!(priv && priv->channel[CTCM_READ] && ndev)) {
+	if (!(priv && priv->channel[CTCM_READ] &&
+	      priv->channel[CTCM_READ]->netdev)) {
 		CTCM_DBF_TEXT(SETUP, CTC_DBF_ERROR, "bfnondev");
 		return -ENODEV;
 	}
+	ndev = priv->channel[CTCM_READ]->netdev;
 
 	rc = kstrtouint(buf, 0, &bs1);
 	if (rc)
-- 
2.35.1