Re: [PATCH v2] PCI: rockchip-dwc: Potential error pointer dereference in probe

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Liam Girdwood" <lgirdwood@gmail.com>,
	"Mark Brown" <broonie@kernel.org>,
	"Shawn Lin" <shawn.lin@rock-chips.com>,
	"Kever Yang" <kever.yang@rock-chips.com>,
	"Simon Xue" <xxm@rock-chips.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH v2] PCI: rockchip-dwc: Potential error pointer dereference in probe
Date: Mon, 23 Aug 2021 17:15:27 +0100	[thread overview]
Message-ID: <20210823161527.GA8289@lpieralisi> (raw)
In-Reply-To: <20210813142648.GA12057@kili>

On Fri, Aug 13, 2021 at 05:26:48PM +0300, Dan Carpenter wrote:
> If devm_regulator_get_optional() returns -ENODEV then it would lead
> to an error pointer dereference on the next line and in the error
> handling code.
> 
> Fixes: e1229e884e19 ("PCI: rockchip-dwc: Add Rockchip RK356X host controller driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: The -ENODEV from devm_regulator_get_optional() has to be handled
>     specially.
> 
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)

I squashed it in with the patch that is fixing, thanks a lot.

Lorenzo

> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index 20cef2e06f66..c9b341e55cbb 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -224,15 +224,17 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
>  
>  	/* DON'T MOVE ME: must be enable before PHY init */
>  	rockchip->vpcie3v3 = devm_regulator_get_optional(dev, "vpcie3v3");
> -	if (IS_ERR(rockchip->vpcie3v3))
> +	if (IS_ERR(rockchip->vpcie3v3)) {
>  		if (PTR_ERR(rockchip->vpcie3v3) != -ENODEV)
>  			return dev_err_probe(dev, PTR_ERR(rockchip->vpcie3v3),
>  					"failed to get vpcie3v3 regulator\n");
> -
> -	ret = regulator_enable(rockchip->vpcie3v3);
> -	if (ret) {
> -		dev_err(dev, "failed to enable vpcie3v3 regulator\n");
> -		return ret;
> +		rockchip->vpcie3v3 = NULL;
> +	} else {
> +		ret = regulator_enable(rockchip->vpcie3v3);
> +		if (ret) {
> +			dev_err(dev, "failed to enable vpcie3v3 regulator\n");
> +			return ret;
> +		}
>  	}
>  
>  	ret = rockchip_pcie_phy_init(rockchip);
> @@ -255,7 +257,8 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
>  deinit_phy:
>  	rockchip_pcie_phy_deinit(rockchip);
>  disable_regulator:
> -	regulator_disable(rockchip->vpcie3v3);
> +	if (rockchip->vpcie3v3)
> +		regulator_disable(rockchip->vpcie3v3);
>  
>  	return ret;
>  }
> -- 
> 2.20.1
> 