[ 111/150] powerpc/eeh: Fix crash when adding a device in a slot with DDW

Greg Kroah-Hartman
2013-02-27T00:52:45Z

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