From: Rafael J. Wysocki <rjw@xxxxxxx> acpi_get_pci_dev() 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. However, during resume from a sleep state, as well as at startup, we may get a dock notification, via dock_acpi_notifier registered by dock_init(), for a docking station device that is present in the ACPI tables, but not physically accessible at the moment. In that situation, the device appears to be below a PCI bridge whose 'subordinate' field is NULL. This, in turn, causes acpi_get_pci_dev() to trigger a NULL pointer dereference. To fix this issue make acpi_get_pci_dev() check if pdev->subordinate is not NULL for every device it finds in the path between the root bridge and the device it's supposed to get to and return NULL if the "target" device is not really accessible. Fixes http://bugzilla.kernel.org/show_bug.cgi?id=14129, which is a regression from 2.6.30. Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> Reported-by: Danny Feng <dfeng@xxxxxxxxxx> Tested-by: chepioq <chepioq@xxxxxxxxx> --- drivers/acpi/pci_root.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) Index: linux-2.6/drivers/acpi/pci_root.c =================================================================== --- linux-2.6.orig/drivers/acpi/pci_root.c +++ linux-2.6/drivers/acpi/pci_root.c @@ -389,6 +389,18 @@ struct pci_dev *acpi_get_pci_dev(acpi_ha pbus = pdev->subordinate; pci_dev_put(pdev); + + /* + * During resume from a sleep state we can get a dock + * notification for a device that is present in ACPI tables, + * but not physically accessible at the moment, so tell the + * caller it's not present in that case. + */ + if (!pbus) { + dev_info(&pdev->dev, "Secondary bus not present\n"); + pdev = NULL; + break; + } } out: list_for_each_entry_safe(node, tmp, &device_list, node) -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
