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Date:   Thu, 1 Apr 2021 10:45:20 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     Thierry Reding <thierry.reding@gmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Mathias Nyman <mathias.nyman@intel.com>,
        JC Kuo <jckuo@nvidia.com>, Jon Hunter <jonathanh@nvidia.com>,
        linux-tegra@vger.kernel.org, linux-phy@lists.infradead.org,
        linux-usb@vger.kernel.org
Subject: Re: [PATCH v8 03/13] phy: tegra: xusb: Move usb3 port init for
 Tegra210
Message-ID: <YGVW6LEZM2w+dyJ8@vkoul-mobl.Dlink>
References: <20210325164057.793954-1-thierry.reding@gmail.com>
 <20210325164057.793954-4-thierry.reding@gmail.com>
 <YGMx5cLmX+d48XKO@vkoul-mobl.Dlink>
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On 31-03-21, 18:32, Thierry Reding wrote:
> On Tue, Mar 30, 2021 at 07:42:53PM +0530, Vinod Koul wrote:
> > Hi Thierry,
> > 
> > On 25-03-21, 17:40, Thierry Reding wrote:
> > 
> > > +static struct tegra_xusb_usb3_port *
> > > +tegra210_lane_to_usb3_port(struct tegra_xusb_lane *lane)
> > > +{
> > > +	int port;
> > > +
> > > +	if (!lane || !lane->pad || !lane->pad->padctl)
> > > +		return NULL;
> > 
> > This looks problematic to me, so if lane is NULL, it will still go ahead
> > and check lane->pad which would result in NULL pointer dereference.
> 
> No, this isn't going to result in a NULL pointer dereference because the
> compiler will short-circuit this if the first expression is true. If the
> lane parameter is NULL, then the entire expression is going to be true
> no matter what lane->pad and lane->pad->padctl evaluate to (because of
> the logical OR) and hence the compiler knows that it can skip the rest.

Yes, that is correct. I assumed wrongly, so:

Acked-By: Vinod Koul <vkoul@kernel.org>


-- 
~Vinod