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From:   Heiko =?ISO-8859-1?Q?St=FCbner?= <heiko@sntech.de>
To:     Yizhuo <yzhai003@ucr.edu>
Cc:     csong@cs.ucr.edu, zhiyunq@cs.ucr.edu,
        Kishon Vijay Abraham I <kishon@ti.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org
Subject: Re: [PATCH] phy: rockchip-typec: Variable "val" of function rockchip_usb3_phy_power_on() could be uninitialized
Date:   Tue, 12 Feb 2019 11:49:51 +0100
Message-ID: <3410531.oxWKaip9ZE@diego>
In-Reply-To: <20190206021810.21596-1-yzhai003@ucr.edu>
References: <20190206021810.21596-1-yzhai003@ucr.edu>
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Am Mittwoch, 6. Februar 2019, 03:18:10 CET schrieb Yizhuo:
> In function rockchip_usb3_phy_power_on(), local variable
> "val" could be uninitialized if function regmap_read()
> returns -EINVAL. However, this value is directly used in
> later context. This is potentially unsafe.

While highly unlikely case (GRF-registers are mmio-based),
it's still nicer to go the clean way, so

Reviewed-by: Heiko Stuebner <heiko@sntech.de>

> Signed-off-by: Yizhuo <yzhai003@ucr.edu>
> ---
>  drivers/phy/rockchip/phy-rockchip-typec.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-typec.c
> b/drivers/phy/rockchip/phy-rockchip-typec.c index
> a958c9bced01..b1e24418cb2d 100644
> --- a/drivers/phy/rockchip/phy-rockchip-typec.c
> +++ b/drivers/phy/rockchip/phy-rockchip-typec.c
> @@ -716,7 +716,10 @@ static int rockchip_usb3_phy_power_on(struct phy *phy)
> 
>  	/* wait TCPHY for pipe ready */
>  	for (timeout = 0; timeout < 100; timeout++) {
> -		regmap_read(tcphy->grf_regs, reg->offset, &val);
> +		ret = regmap_read(tcphy->grf_regs, reg->offset, &val);
> +		if (ret)
> +			goto unlock_ret;
> +
>  		if (!(val & BIT(reg->enable_bit))) {
>  			tcphy->mode |= new_mode & (MODE_DFP_USB | MODE_UFP_USB);
>  			goto unlock_ret;