On Tue, Feb 02, 2010 at 03:46:28PM -0200, Breno Leitao wrote:
> During a EEH recover, the pci_dev structure can be null, mainly if an
> eeh event is detected during cpi config operation. In this case, the
> pci_dev will not be known (and will be null) and the kernel will crash
> with the following message:
>
> Unable to handle kernel paging request for data at address 0x000000a0
> Faulting instruction address: 0xc00000000006b8b4
> Oops: Kernel access of bad area, sig: 11 [#1]
>
> NIP [c00000000006b8b4] .eeh_event_handler+0x10c/0x1a0
> LR [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0
> Call Trace:
> [c0000003a80dff00] [c00000000006b8a8] .eeh_event_handler+0x100/0x1a0
> [c0000003a80dff90] [c000000000031f1c] .kernel_thread+0x54/0x70
>
> The bug occurs because pci_name() tries to access a null pointer.
> This patch just guarantee that pci_name() is not called on Null pointers.
>
> Signed-off-by: Breno Leitao <lei...@linux.vnet.ibm.com>
> Signed-off-by: Linas Vepstas <linasveps...@gmail.com>
> ---
> arch/powerpc/include/asm/ppc-pci.h | 7 +++++++
> arch/powerpc/platforms/pseries/eeh.c | 4 ++--
> arch/powerpc/platforms/pseries/eeh_driver.c | 4 ++--
> arch/powerpc/platforms/pseries/eeh_event.c | 2 +-
> 4 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/ppc-pci.h
> b/arch/powerpc/include/asm/ppc-pci.h
> index 2828f9d..724dbe2 100644
> --- a/arch/powerpc/include/asm/ppc-pci.h
> +++ b/arch/powerpc/include/asm/ppc-pci.h
> @@ -137,6 +137,13 @@ struct device_node * find_device_pe(struct device_node
> *dn);
> void eeh_sysfs_add_device(struct pci_dev *pdev);
> void eeh_sysfs_remove_device(struct pci_dev *pdev);
>
> +static inline const char *eeh_pci_name(struct pci_dev *pdev)
> +{
> + if (NULL==pdev)
> + return "<null>";
> + return pci_name(pdev);
What about:
return pdev ? pci_name(pdev) : "<null>";
> +}
> +
> #endif /* CONFIG_EEH */
>
> #else /* CONFIG_PCI */
> diff --git a/arch/powerpc/platforms/pseries/eeh.c
> b/arch/powerpc/platforms/pseries/eeh.c
> index ccd8dd0..f9360fe 100644
> --- a/arch/powerpc/platforms/pseries/eeh.c
> +++ b/arch/powerpc/platforms/pseries/eeh.c
> @@ -491,7 +491,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct
> pci_dev *dev)
> pdn->eeh_mode & EEH_MODE_NOCHECK) {
> ignored_check++;
> pr_debug("EEH: Ignored check (%x) for %s %s\n",
> - pdn->eeh_mode, pci_name (dev), dn->full_name);
> + pdn->eeh_mode, eeh_pci_name (dev), dn->full_name);
No space after function name, please.
> return 0;
> }
>
> @@ -515,7 +515,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct
> pci_dev *dev)
> printk (KERN_ERR "EEH: %d reads ignored for recovering
> device at "
> "location=%s driver=%s pci addr=%s\n",
> pdn->eeh_check_count, location,
> - dev->driver->name, pci_name(dev));
> + dev->driver->name, eeh_pci_name(dev));
ditto
> printk (KERN_ERR "EEH: Might be infinite loop in %s
> driver\n",
> dev->driver->name);
> dump_stack();
> diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c
> b/arch/powerpc/platforms/pseries/eeh_driver.c
> index ef8e454..8f948a0 100644
> --- a/arch/powerpc/platforms/pseries/eeh_driver.c
> +++ b/arch/powerpc/platforms/pseries/eeh_driver.c
> @@ -337,7 +337,7 @@ struct pci_dn * handle_eeh_events (struct eeh_event
> *event)
> location = location ? location : "unknown";
> printk(KERN_ERR "EEH: Error: Cannot find partition endpoint "
> "for location=%s pci addr=%s\n",
> - location, pci_name(event->dev));
> + location, eeh_pci_name(event->dev));
> return NULL;
> }
>
> @@ -368,7 +368,7 @@ struct pci_dn * handle_eeh_events (struct eeh_event
> *event)
> pci_str = pci_name (frozen_pdn->pcidev);
> drv_str = pcid_name (frozen_pdn->pcidev);
> } else {
> - pci_str = pci_name (event->dev);
> + pci_str = eeh_pci_name (event->dev);
ditto
> drv_str = pcid_name (event->dev);
> }
>
> diff --git a/arch/powerpc/platforms/pseries/eeh_event.c
> b/arch/powerpc/platforms/pseries/eeh_event.c
> index ddb80f5..ec5df8f 100644
> --- a/arch/powerpc/platforms/pseries/eeh_event.c
> +++ b/arch/powerpc/platforms/pseries/eeh_event.c
> @@ -80,7 +80,7 @@ static int eeh_event_handler(void * dummy)
> eeh_mark_slot(event->dn, EEH_MODE_RECOVERING);
>
> printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n",
> - pci_name(event->dev));
> + eeh_pci_name(event->dev));
>
> pdn = handle_eeh_events(event);
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--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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