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From:   Arnd Bergmann <arnd@arndb.de>
To:     Igor Mitsyanko <imitsyanko@quantenna.com>,
        Avinash Patil <avinashp@quantenna.com>,
        Sergey Matyukevich <smatyukevich@quantenna.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Vasily Ulyanov <vulyanov@quantenna.com>,
        Andrey Shevchenko <ashevchenko@quantenna.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, linux-wireless@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] qtnfmac: avoid uninitialized variable access
Date:   Tue,  9 Oct 2018 17:57:35 +0200
Message-Id: <20181009155757.494212-1-arnd@arndb.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When qtnf_trans_send_cmd_with_resp() fails, we have not yet initialized
'resp', as pointed out by a valid gcc warning:

drivers/net/wireless/quantenna/qtnfmac/commands.c: In function 'qtnf_cmd_send_with_reply':
drivers/net/wireless/quantenna/qtnfmac/commands.c:133:54: error: 'resp' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Since 'resp_skb' is also not set here, we can skip all further
processing and just print the warning and return the failure code.

Fixes: c6ed298ffe09 ("qtnfmac: cleanup and unify command error handling")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/quantenna/qtnfmac/commands.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/quantenna/qtnfmac/commands.c b/drivers/net/wireless/quantenna/qtnfmac/commands.c
index bfdc1ad30c13..9b211459684a 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/commands.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/commands.c
@@ -111,7 +111,7 @@ static int qtnf_cmd_send_with_reply(struct qtnf_bus *bus,
 
 	ret = qtnf_trans_send_cmd_with_resp(bus, cmd_skb, &resp_skb);
 	if (ret)
-		goto out;
+		goto out_noresp;
 
 	resp = (const struct qlink_resp *)resp_skb->data;
 	ret = qtnf_cmd_check_reply_header(resp, cmd_id, mac_id, vif_id,
@@ -132,6 +132,7 @@ static int qtnf_cmd_send_with_reply(struct qtnf_bus *bus,
 	if (!ret && resp)
 		return qtnf_cmd_resp_result_decode(le16_to_cpu(resp->result));
 
+out_noresp:
 	pr_warn("VIF%u.%u: cmd 0x%.4X failed: %d\n",
 		mac_id, vif_id, le16_to_cpu(cmd->cmd_id), ret);
 
-- 
2.18.0