Re: [PATCH 0/2] PCI: PCI-E MPS bug fixes

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> DNS issue with kernel.org when the patches went out caused it to not
> get out to any of the mailing lists.
> 
> In Linux' github tree
> Patch 1/2 is commit 5307f6d5fb12fd01f9f321bc4a8fd77e74858647
> Patch 2/2 is commit ed2888e906b56769b4ffabb9c577190438aa68b8
> 
> > When using "safe" mode, I get a crash in pcie_find_smpss(). Patch below.
> >
> > From 1b542d690323fab332e61099193d598c5c515d13 Mon Sep 17 00:00:00 2001
> > From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Date: Tue, 13 Sep 2011 15:16:33 -0300
> > Subject: [PATCH] pci: Don't crash when reading mpss from root complex
> >
> > In pcie_find_smpss(), we have the following statement:
> >
> >        if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
> >            dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))
> >
> > The problem is that at least on my machine, this gets called for the
> > root complex (virtual P2P bridge), and dev->bus->self is NULL since
> > the parent bus for this is not itself anchor to a PCI device.
> >
> > This adds the necessary NULL check.
> >
> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> Good catch.
> 
> Acked-by: Jon Mason <mason@myri.com>

Linus, please apply.

Cheers
Ben.

> > ---
> >  drivers/pci/probe.c |    3 ++-
> >  1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 8473727..09d1c0f 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -1351,7 +1351,8 @@ static int pcie_find_smpss(struct pci_dev *dev, void *data)
> >         * will occur as normal.
> >         */
> >        if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) ||
> > -           dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))
> > +            (dev->bus->self &&
> > +             dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)))
> >                *smpss = 0;
> >
> >        if (*smpss > dev->pcie_mpss)
> > --
> > 1.7.4.1
> >
> >
> >
> >
> >
> >
> >
> --
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