linux-kernel - [PATCH] net: stmmac: Variable "val" in function sun8i_dwmac_set

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Message-Id: <20190205221559.17545-1-yzhai003@ucr.edu>
Date:   Tue,  5 Feb 2019 14:15:59 -0800
From:   Yizhuo <yzhai003@....edu>
To:     unlisted-recipients:; (no To-header on input)
Cc:     csong@...ucr.edu, zhiyunq@...ucr.edu, Yizhuo <yzhai003@....edu>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Chen-Yu Tsai <wens@...e.org>, netdev@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] net: stmmac: Variable "val" in function sun8i_dwmac_set_syscon() could be uninitialized

In function sun8i_dwmac_set_syscon(), local variable "val" could
be uninitialized if function regmap_read() returns -EINVAL.
However, it will be used directly in the if statement, which
is potentially unsafe.

Signed-off-by: Yizhuo <yzhai003@....edu>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
index 39c2122a4f26..11d481c9e7ab 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
@@ -639,9 +639,14 @@ static int sun8i_dwmac_set_syscon(struct stmmac_priv *priv)
 	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
 	struct device_node *node = priv->device->of_node;
 	int ret;
-	u32 reg, val;
+	u32 reg, val = 0;
+
+	ret = regmap_read(gmac->regmap, SYSCON_EMAC_REG, &val);
+	if (ret) {
+		dev_err(priv->device, "Fail to read SYSCON_EMAC_REG.\n");
+		return ret;
+	}
 
-	regmap_read(gmac->regmap, SYSCON_EMAC_REG, &val);
 	reg = gmac->variant->default_syscon_value;
 	if (reg != val)
 		dev_warn(priv->device,
-- 
2.17.1