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    SubjectRe: [ 008/153] powerpc/eeh: Fix crash when adding a device in a slot with DDW
    On Fri, Mar 08, 2013 at 03:29:55AM +0000, Ben Hutchings wrote:
    > On Fri, 2013-03-08 at 13:51 +1100, Michael Neuling wrote:
    > > This patch is breaking the celleb_defconfig on powerpc with:
    > >
    > > arch/powerpc/kernel/of_platform.c: In function 'of_pci_phb_probe':
    > > arch/powerpc/kernel/of_platform.c:95:2: error: implicit declaration of
    > > function 'eeh_add_sysfs_files' [-Werror=implicit-function-declaration]
    >
    > In 3.2 this file doesn't (directly) include <asm/eeh.h> which is where
    > the definition was added. In mainline it does.
    >
    > Assuming that this change is actually required for 3.2 (which I'm not
    > sure about), I suppose we just need to add the #include.
    >
    > Ben.
    >

    This is not required for 3.2. The patch that *may* have broken DLPAR
    (39baadbf36cee3ede5fdb8a34006d9109e5e2570) was introduced between 3.3
    and 3.4.

    Regards.
    Cascardo.

    > > Mikey
    > >
    > > On Mon, Mar 4, 2013 at 2:37 PM, Ben Hutchings <ben@decadent.org.uk> wrote:
    > > > 3.2-stable review patch. If anyone has any objections, please let me know.
    > > >
    > > > ------------------
    > > >
    > > > From: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
    > > >
    > > > commit 6a040ce72598159a74969a2d01ab0ba5ee6536b3 upstream.
    > > >
    > > > The DDW code uses a eeh_dev struct from the pci_dev. However, this is
    > > > not set until eeh_add_device_late is called.
    > > >
    > > > Since pci_bus_add_devices is called before eeh_add_device_late, the PCI
    > > > devices are added to the bus, making drivers' probe hooks to be called.
    > > > These will call set_dma_mask, which will call the DDW code, which will
    > > > require the eeh_dev struct from pci_dev. This would result in a crash,
    > > > due to a NULL dereference.
    > > >
    > > > Calling eeh_add_device_late after pci_bus_add_devices would make the
    > > > system BUG, because device files shouldn't be added to devices there
    > > > were not added to the system. So, a new function is needed to add such
    > > > files only after pci_bus_add_devices have been called.
    > > >
    > > > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com>
    > > > Acked-by: Gavin Shan <shangw@linux.vnet.ibm.com>
    > > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    > > > [bwh: Backported to 3.2: adjust context]
    > > > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    > > > ---
    > > > arch/powerpc/include/asm/eeh.h | 3 +++
    > > > arch/powerpc/kernel/of_platform.c | 3 +++
    > > > arch/powerpc/kernel/pci-common.c | 7 +++++--
    > > > arch/powerpc/platforms/pseries/eeh.c | 24 +++++++++++++++++++++++-
    > > > 4 files changed, 34 insertions(+), 3 deletions(-)
    > > >
    > > > --- a/arch/powerpc/include/asm/eeh.h
    > > > +++ b/arch/powerpc/include/asm/eeh.h
    > > > @@ -61,6 +61,7 @@ void __init pci_addr_cache_build(void);
    > > > */
    > > > void eeh_add_device_tree_early(struct device_node *);
    > > > void eeh_add_device_tree_late(struct pci_bus *);
    > > > +void eeh_add_sysfs_files(struct pci_bus *);
    > > >
    > > > /**
    > > > * eeh_remove_device_recursive - undo EEH for device & children.
    > > > @@ -105,6 +106,8 @@ static inline void eeh_add_device_tree_e
    > > >
    > > > static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
    > > >
    > > > +static inline void eeh_add_sysfs_files(struct pci_bus *bus) { }
    > > > +
    > > > static inline void eeh_remove_bus_device(struct pci_dev *dev) { }
    > > > #define EEH_POSSIBLE_ERROR(val, type) (0)
    > > > #define EEH_IO_ERROR_VALUE(size) (-1UL)
    > > > --- a/arch/powerpc/kernel/of_platform.c
    > > > +++ b/arch/powerpc/kernel/of_platform.c
    > > > @@ -91,6 +91,9 @@ static int __devinit of_pci_phb_probe(st
    > > > /* Add probed PCI devices to the device model */
    > > > pci_bus_add_devices(phb->bus);
    > > >
    > > > + /* sysfs files should only be added after devices are added */
    > > > + eeh_add_sysfs_files(phb->bus);
    > > > +
    > > > return 0;
    > > > }
    > > >
    > > > --- a/arch/powerpc/kernel/pci-common.c
    > > > +++ b/arch/powerpc/kernel/pci-common.c
    > > > @@ -1536,11 +1536,14 @@ void pcibios_finish_adding_to_bus(struct
    > > > pcibios_allocate_bus_resources(bus);
    > > > pcibios_claim_one_bus(bus);
    > > >
    > > > + /* Fixup EEH */
    > > > + eeh_add_device_tree_late(bus);
    > > > +
    > > > /* Add new devices to global lists. Register in proc, sysfs. */
    > > > pci_bus_add_devices(bus);
    > > >
    > > > - /* Fixup EEH */
    > > > - eeh_add_device_tree_late(bus);
    > > > + /* sysfs files should only be added after devices are added */
    > > > + eeh_add_sysfs_files(bus);
    > > > }
    > > > EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
    > > >
    > > > --- a/arch/powerpc/platforms/pseries/eeh.c
    > > > +++ b/arch/powerpc/platforms/pseries/eeh.c
    > > > @@ -1238,7 +1238,6 @@ static void eeh_add_device_late(struct p
    > > > pdn->pcidev = dev;
    > > >
    > > > pci_addr_cache_insert_device(dev);
    > > > - eeh_sysfs_add_device(dev);
    > > > }
    > > >
    > > > void eeh_add_device_tree_late(struct pci_bus *bus)
    > > > @@ -1257,6 +1256,29 @@ void eeh_add_device_tree_late(struct pci
    > > > EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
    > > >
    > > > /**
    > > > + * eeh_add_sysfs_files - Add EEH sysfs files for the indicated PCI bus
    > > > + * @bus: PCI bus
    > > > + *
    > > > + * This routine must be used to add EEH sysfs files for PCI
    > > > + * devices which are attached to the indicated PCI bus. The PCI bus
    > > > + * is added after system boot through hotplug or dlpar.
    > > > + */
    > > > +void eeh_add_sysfs_files(struct pci_bus *bus)
    > > > +{
    > > > + struct pci_dev *dev;
    > > > +
    > > > + list_for_each_entry(dev, &bus->devices, bus_list) {
    > > > + eeh_sysfs_add_device(dev);
    > > > + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
    > > > + struct pci_bus *subbus = dev->subordinate;
    > > > + if (subbus)
    > > > + eeh_add_sysfs_files(subbus);
    > > > + }
    > > > + }
    > > > +}
    > > > +EXPORT_SYMBOL_GPL(eeh_add_sysfs_files);
    > > > +
    > > > +/**
    > > > * eeh_remove_device - undo EEH setup for the indicated pci device
    > > > * @dev: pci device to be removed
    > > > *
    > > >
    > > >
    > > > --
    > > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    > > > the body of a message to majordomo@vger.kernel.org
    > > > More majordomo info at http://vger.kernel.org/majordomo-info.html
    > > > Please read the FAQ at http://www.tux.org/lkml/
    > > >
    > >
    >
    > --
    > Ben Hutchings
    > Always try to do things in chronological order;
    > it's less confusing that way.




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