The following commit has been merged in the linux branch: commit 497fb54f578efd2b479727bc88d5ef942c0a1e2d Author: Rafael J. Wysocki rjw@sisk.pl Date: Tue Oct 13 01:01:57 2009 +0200

ACPI / PCI: Fix NULL pointer dereference in acpi_get_pci_dev() (rev. 2)

acpi_get_pci_dev() may be called for a non-PCI device, in which case it should return NULL. However, it assumes that every handle it finds in the ACPI CA name space, between given device handle and the PCI root bridge handle, corresponds to a PCI-to-PCI bridge with an existing secondary bus. For this reason, when it finds a struct pci_dev object corresponding to one of them, it doesn't check if its 'subordinate' field is a valid pointer. This obviously leads to a NULL pointer dereference if acpi_get_pci_dev() is called for a non-PCI device with a PCI parent which is not a bridge.

To fix this issue make acpi_get_pci_dev() check if pdev->subordinate is not NULL for every device it finds on the path between the root bridge and the device it's supposed to get to and return NULL if the "target" device cannot be found.

http://bugzilla.kernel.org/show_bug.cgi?id=14129 (worked in 2.6.30, regression in 2.6.31)

Signed-off-by: Rafael J. Wysocki rjw@sisk.pl Reported-by: Danny Feng dfeng@redhat.com Reviewed-by: Alex Chiang achiang@hp.com Tested-by: chepioq chepioq@gmail.com Signed-off-by: Len Brown len.brown@intel.com

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 3112221..1af8081 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -389,6 +389,17 @@ struct pci_dev *acpi_get_pci_dev(acpi_handle handle)

pbus = pdev->subordinate; pci_dev_put(pdev); + + /* + * This function may be called for a non-PCI device that has a + * PCI parent (eg. a disk under a PCI SATA controller). In that + * case pdev->subordinate will be NULL for the parent. + */ + if (!pbus) { + dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n"); + pdev = NULL; + break; + } } out: list_for_each_entry_safe(node, tmp, &device_list, node)