From: Rob Herring <robh@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: "Dan Carpenter" <dan.carpenter@oracle.com>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Simon Xue" <xxm@rock-chips.com>,
"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>,
"Kever Yang" <kever.yang@rock-chips.com>,
"Shawn Lin" <shawn.lin@rock-chips.com>,
PCI <linux-pci@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
"open list:ARM/Rockchip SoC..."
<linux-rockchip@lists.infradead.org>,
kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] PCI: rockchip-dwc: Potential error pointer dereference in probe
Date: Fri, 13 Aug 2021 10:57:44 -0500 [thread overview]
Message-ID: <CAL_JsqLWVLRDdkR62BSv69oW3QCLVebgpU1TKtxvzZmD4wuP4Q@mail.gmail.com> (raw)
In-Reply-To: <81b9a25d-f12f-90e0-0b05-b5e396f14c08@arm.com>
On Fri, Aug 13, 2021 at 8:47 AM Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 2021-08-13 14:34, Rob Herring wrote:
> > On Fri, Aug 13, 2021 at 7:55 AM Robin Murphy <robin.murphy@arm.com> wrote:
> >>
> >> On 2021-08-13 12:33, Dan Carpenter wrote:
> >>> If devm_regulator_get_optional() returns an error pointer, then we
> >>> should return it to the user. The current code makes an exception
> >>> for -ENODEV that will result in an error pointer dereference on the
> >>> next line when it calls regulator_enable(). Remove the exception.
> >>
> >> Doesn't this break the apparent intent of the regulator being optional,
> >> though?
> >
> > I'm pretty sure 'optional' means ENODEV is never returned. So there
> > wasn't any real problem, but the check was unnecessary.
>
> In fact it's the other way round - "optional" in this case is for when
> the supply may legitimately not exist so the driver may or may not need
> to handle it, so it can return -ENODEV if a regulator isn't described by
> firmware. A non-optional regulator is assumed to represent a necessary
> supply, so if there's nothing described by firmware you get the (valid)
> dummy regulator back.
Ah yes, regulators is the oddball. Surely no one else will assume the
same behavior of _optional() variants across subsystems... ;)
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next prev parent reply other threads:[~2021-08-13 15:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-13 11:33 [PATCH] PCI: rockchip-dwc: Potential error pointer dereference in probe Dan Carpenter
2021-08-13 12:55 ` Robin Murphy
2021-08-13 13:34 ` Rob Herring
2021-08-13 13:47 ` Robin Murphy
2021-08-13 15:57 ` Rob Herring [this message]
2021-08-13 16:01 ` Mark Brown
2021-08-13 13:54 ` Dan Carpenter
2021-08-13 14:01 ` Robin Murphy
2021-08-13 14:12 ` Dan Carpenter
2021-08-13 14:26 ` [PATCH v2] " Dan Carpenter
2021-08-23 16:15 ` Lorenzo Pieralisi
2021-08-13 14:32 ` [PATCH] " Mark Brown
2021-08-13 15:00 ` Robin Murphy
2021-08-13 15:30 ` Mark Brown
2021-08-13 15:45 ` Dan Carpenter
2021-08-13 15:53 ` Mark Brown
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