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SubjectRe: [ 008/153] powerpc/eeh: Fix crash when adding a device in a slot with DDW
From
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]

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
> *
>
>
> --
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