Re: [PCI] BUG: unable to handle kernel

[Murali Karicheri]

On 03/06/2015 12:58 PM, Murali Karicheri wrote:
> On 03/06/2015 11:55 AM, Guenter Roeck wrote:
> > On Fri, Mar 06, 2015 at 10:48:59AM -0500, Murali Karicheri wrote:
> > [ ... ]
> >
> > > > From 098b4f5e4ab9407fbdbfcca3a91785c17e25cf03 Mon Sep 17 00:00:00 2001
> > > From: Murali Karicheri<m-karicheri2@xxxxxx>
> > > Date: Fri, 6 Mar 2015 10:23:08 -0500
> > > Subject: [PATCH] pci: of : fix kernel crash
> > >
> > > This is a debug patch to root cause the kernel crash
> > >
> > > commit 0b2af171520e5d5e7d5b5f479b90a6a5014d9df6
> > >
> > > PCI: Update DMA configuration from DT
> > >
> > > Signed-off-by: Murali Karicheri<m-karicheri2@xxxxxx>
> > > ---
> > > drivers/of/of_pci.c | 8 ++++++++
> > > drivers/pci/host-bridge.c | 5 +++++
> > > 2 files changed, 13 insertions(+)
> > >
> > > diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> > > index 86d3c38..5a59fb8 100644
> > > --- a/drivers/of/of_pci.c
> > > +++ b/drivers/of/of_pci.c
> > > @@ -129,6 +129,14 @@ void of_pci_dma_configure(struct pci_dev *pci_dev)
> > > struct device *dev =&pci_dev->dev;
> > > struct device *bridge = pci_get_host_bridge_device(pci_dev);
> > >
> > > + if (!bridge || !bridge->parent) {
> > > + if (!bridge)
> > > + pr_err("PCI bridge not found\n");
> > > + if (!bridge->parent)
> > > + pr_err("PCI bridge parent not found\n");
> >
> > You'll see a crash here if bridge is NULL. Maybe add an else before
> > the second
> > if statement ? Also, dev_err might be a bit more useful and would be
> > available.
> Fixed and attached.
>
> Murali
> > Thanks,
> > Guenter
> >
> > > + return;
> > > + }
> > > +
> > > of_dma_configure(dev, bridge->parent->of_node);
> > > pci_put_host_bridge_device(bridge);
> > > }
> > > diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> > > index 3e5bbf9..ef2ab51 100644
> > > --- a/drivers/pci/host-bridge.c
> > > +++ b/drivers/pci/host-bridge.c
> > > @@ -28,6 +28,11 @@ struct device *pci_get_host_bridge_device(struct
> > > pci_dev *dev)
> > > struct pci_bus *root_bus = find_pci_root_bus(dev->bus);
> > > struct device *bridge = root_bus->bridge;
> > >
> > > + if (!bridge) {
> > > + pr_err("PCI: bridge not found\n");
> > > + return NULL;
> > > + }
> > > +
> > > kobject_get(&bridge->kobj);
> > > return bridge;
> > > }
> > > --
> > > 1.7.9.5
BJorn,

Any chance of applying the attached debug patch to see if this fixes and 
provide some additional information on this BUG? Not sure who will pick 
this one and apply.

--
Murali Karicheri
Linux Kernel, Texas Instruments
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