[ 3.5.y.z extended stable ] Patch "powerpc/eeh: Fix crash when adding a device in a slot with" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    powerpc/eeh: Fix crash when adding a device in a slot with

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From f5e56b84c4d3d953f80c2452dc4f8a44d9750968 Mon Sep 17 00:00:00 2001
From: Thadeu Lima de Souza Cascardo <cascardo at linux.vnet.ibm.com>
Date: Fri, 28 Dec 2012 09:13:19 +0000
Subject: [PATCH] powerpc/eeh: Fix crash when adding a device in a slot with
 DDW

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 at linux.vnet.ibm.com>
Acked-by: Gavin Shan <shangw at linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
[ luis: adjust context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/powerpc/include/asm/eeh.h       |  4 ++++
 arch/powerpc/kernel/of_platform.c    |  3 +++
 arch/powerpc/kernel/pci-common.c     |  7 +++++--
 arch/powerpc/platforms/pseries/eeh.c | 24 +++++++++++++++++++++++-
 4 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index d60f998..c487556 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -130,6 +130,7 @@ int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev);
 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 *);
 void eeh_remove_bus_device(struct pci_dev *);

 /**
@@ -183,7 +184,10 @@ 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) { }
+
 #define EEH_POSSIBLE_ERROR(val, type) (0)
 #define EEH_IO_ERROR_VALUE(size) (-1UL)
 #endif /* CONFIG_EEH */
diff --git a/arch/powerpc/kernel/of_platform.c b/arch/powerpc/kernel/of_platform.c
index 2049f2d..2089fbd 100644
--- a/arch/powerpc/kernel/of_platform.c
+++ b/arch/powerpc/kernel/of_platform.c
@@ -95,6 +95,9 @@ 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 8e78e93..41d69fc 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1458,11 +1458,14 @@ 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 9a0b5f5..b1d91b5 100644
--- a/arch/powerpc/platforms/pseries/eeh.c
+++ b/arch/powerpc/platforms/pseries/eeh.c
@@ -1088,7 +1088,6 @@ static void eeh_add_device_late(struct pci_dev *dev)
 	dev->dev.archdata.edev = edev;

 	pci_addr_cache_insert_device(dev);
-	eeh_sysfs_add_device(dev);
 }

 /**
@@ -1115,6 +1114,29 @@ 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
  *
--
1.8.1.2