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    Subject[ 111/150] powerpc/eeh: Fix crash when adding a device in a slot with DDW
    Date
    3.8-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>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    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
    @@ -201,6 +201,7 @@ int eeh_dev_check_failure(struct eeh_dev
    void __init eeh_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 *);
    void eeh_remove_bus_device(struct pci_dev *, int);

    /**
    @@ -240,6 +241,8 @@ 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, int purge_pe) { }

    static inline void eeh_lock(void) { }
    --- a/arch/powerpc/kernel/of_platform.c
    +++ b/arch/powerpc/kernel/of_platform.c
    @@ -95,6 +95,9 @@ static int of_pci_phb_probe(struct platf
    /* 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
    @@ -1477,11 +1477,14 @@ 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
    @@ -788,7 +788,6 @@ static void eeh_add_device_late(struct p
    dev->dev.archdata.edev = edev;

    eeh_addr_cache_insert_dev(dev);
    - eeh_sysfs_add_device(dev);
    }

    /**
    @@ -815,6 +814,29 @@ 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
    * @purge_pe: remove the PE or not



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