Re: [PATCH 2/2] ppc/EEH: fix crash when adding a device in a slot with DDW
From: Gavin Shan <hidden>
Date: 2013-01-04 03:19:47
On Fri, Dec 28, 2012 at 05:13:19PM -0200, Thadeu Lima de Souza Cascardo wrote:
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.
Thanks, Cascardo. The change looks good to me :-) Acked-by: Gavin Shan <redacted>
quoted hunk ↗ jump to hunk
Cc: stable@vger.kernel.org Signed-off-by: Thadeu Lima de Souza Cascardo <redacted> --- 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(-)diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h index b0ef738..0f816da 100644 --- 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 *edev);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_early(struct device_node *dn) { }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) { }diff --git a/arch/powerpc/kernel/of_platform.c b/arch/powerpc/kernel/of_platform.c index c5fc6b2..500dd32 100644 --- 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(struct platform_device *dev)/* 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; }diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index 7f94f76..4d3de7e 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c@@ -1480,11 +1480,14 @@ void pcibios_finish_adding_to_bus(struct pci_bus *bus)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);diff --git a/arch/powerpc/platforms/pseries/eeh.c b/arch/powerpc/platforms/pseries/eeh.c index 9a04322..6b73d6c 100644 --- 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 pci_dev *dev)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_bus *bus)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
Thanks, Gavin