[05/38] Fix pointer dereference before call to pcie_bus_configure_settings

Greg KH
2011-10-11T17:03:40Z

From: Shyam Iyer <shyam.iyer.t@gmail.com>

commit 5307f6d5fb12fd01f9f321bc4a8fd77e74858647 upstream.

Commit b03e7495a862 ("PCI: Set PCI-E Max Payload Size on fabric")
introduced a potential NULL pointer dereference in calls to
pcie_bus_configure_settings due to attempts to access pci_bus self
variables when the self pointer is NULL.

To correct this, verify that the self pointer in pci_bus is non-NULL
before dereferencing it.

Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: Jon Mason <mason@myri.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/pci/acpi.c | 9 +++++++--
drivers/pci/hotplug/pcihp_slot.c | 4 +++-
drivers/pci/probe.c | 3 ---
3 files changed, 10 insertions(+), 6 deletions(-)

--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -366,8 +366,13 @@ struct pci_bus * __devinit pci_acpi_scan
*/
if (bus) {
struct pci_bus *child;
- list_for_each_entry(child, &bus->children, node)
- pcie_bus_configure_settings(child, child->self->pcie_mpss);
+ list_for_each_entry(child, &bus->children, node) {
+ struct pci_dev *self = child->self;
+ if (!self)
+ continue;
+
+ pcie_bus_configure_settings(child, self->pcie_mpss);
+ }
}

if (!bus)
--- a/drivers/pci/hotplug/pcihp_slot.c
+++ b/drivers/pci/hotplug/pcihp_slot.c
@@ -169,7 +169,9 @@ void pci_configure_slot(struct pci_dev *
(dev->class >> 8) == PCI_CLASS_BRIDGE_PCI)))
return;

- pcie_bus_configure_settings(dev->bus, dev->bus->self->pcie_mpss);
+ if (dev->bus && dev->bus->self)
+ pcie_bus_configure_settings(dev->bus,
+ dev->bus->self->pcie_mpss);

memset(&hpp, 0, sizeof(hpp));
ret = pci_get_hp_params(dev, &hpp);
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1461,9 +1461,6 @@ void pcie_bus_configure_settings(struct
{
u8 smpss = mpss;

- if (!bus->self)
- return;
-
if (!pci_is_pcie(bus->self))
return;