From: Samuel Dionne-Riel <samuel@dionne-riel.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Rob Herring <robh@kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Bjorn Helgaas <bhelgaas@google.com>,
devicetree@vger.kernel.org, Frank Rowand <frowand.list@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: Boot failure on gru-scarlet-inx with 5.9-rc2
Date: Thu, 3 Sep 2020 15:21:40 -0400 [thread overview]
Message-ID: <20200903152140.7b6e9c7f@DUFFMAN> (raw)
In-Reply-To: <9be6848cfdbb92865417292feff03cae@kernel.org>
On Thu, 03 Sep 2020 16:59:30 +0100
Marc Zyngier <maz@kernel.org> wrote:
> On 2020-09-03 15:35, Rob Herring wrote:
> > On Thu, Sep 3, 2020 at 3:19 AM Lorenzo Pieralisi
> > <lorenzo.pieralisi@arm.com> wrote:
> >>
> >> Ok I think I understand what the problem is.
> >>
> >> Can you give this patch a shot please ? I think we are
> >> dereferencing a NULL pointer if bus is the root bus and dev == 0,
> >> we can rewrite the check if this patch fixes the issue.
> >
> > Indeed. I checked all the other cases of
> > pci_is_root_bus(bus->parent) and they should be fine because they
> > are only reached if !root_bus.
> >
> > I would restructure the check like this instead:
> >
> > diff --git a/drivers/pci/controller/pcie-rockchip-host.c
> > b/drivers/pci/controller/pcie-rockchip-host.c
> > index 0bb2fb3e8a0b..9b485bea8b92 100644
> > --- a/drivers/pci/controller/pcie-rockchip-host.c
> > +++ b/drivers/pci/controller/pcie-rockchip-host.c
> > @@ -72,14 +72,14 @@ static int rockchip_pcie_valid_device(struct
> > rockchip_pcie *rockchip,
> > struct pci_bus *bus, int dev)
> > {
> > /* access only one slot on each root port */
> > - if (pci_is_root_bus(bus) && dev > 0)
> > - return 0;
> > -
> > - /*
> > - * do not read more than one device on the bus directly
> > attached
> > - * to RC's downstream side.
> > - */
> > - if (pci_is_root_bus(bus->parent) && dev > 0)
> > + if (pci_is_root_bus(bus))
> > + if (dev > 0)
> > + return 0;
> > + else if (pci_is_root_bus(bus->parent) && dev > 0)
>
> Careful here, this else is relative to the *closest* if,
> and not what the indentation suggests...
>
> > + /*
> > + * do not read more than one device on the bus
> > directly attached
> > + * to RC's downstream side.
> > + */
> > return 0;
> >
> > return 1;
>
>
> M.
Both patches work fine. They both allow the device to boot and Wi-Fi to
work as expected.
I will echo Marc's concerns over the indentation. I am only casually
acquainted with C and this indentation would bring to wrong conclusions
if it hadn't been pointed out to me.
Cc me on an eventual patch, FWIW I can give it a final test just in
case.
Thanks again,
--
Samuel Dionne-Riel
prev parent reply other threads:[~2020-09-03 19:21 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-29 20:54 Boot failure on gru-scarlet-inx with 5.9-rc2 Samuel Dionne-Riel
2020-08-30 9:41 ` Marc Zyngier
2020-08-30 20:19 ` Samuel Dionne-Riel
2020-08-31 7:18 ` Samuel Dionne-Riel
2020-08-31 9:27 ` Marc Zyngier
2020-09-01 3:45 ` Samuel Dionne-Riel
2020-09-01 15:37 ` Marc Zyngier
2020-09-01 16:42 ` Lorenzo Pieralisi
2020-09-01 18:33 ` Samuel Dionne-Riel
2020-09-02 16:01 ` Lorenzo Pieralisi
2020-09-03 3:47 ` Samuel Dionne-Riel
2020-09-03 9:19 ` Lorenzo Pieralisi
2020-09-03 14:35 ` Rob Herring
2020-09-03 15:59 ` Marc Zyngier
2020-09-03 19:21 ` Samuel Dionne-Riel [this message]
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