From: Rafael J. Wysocki Date: Mon, 3 Feb 2014 01:22:07 +0000 (+0100) Subject: ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order X-Git-Tag: firefly_0821_release~176^2~4461^2~7 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=2d7c1b77dd59387070aab355532dd157f888325c;p=firefly-linux-kernel-4.4.55.git ACPI / hotplug / PCI: Remove entries from bus->devices in reverse order According to the changelog of commit 29ed1f29b68a (PCI: pciehp: Fix null pointer deref when hot-removing SR-IOV device) it is unsafe to walk the bus->devices list of a PCI bus and remove devices from it in direct order, because that may lead to NULL pointer dereferences related to virtual functions. For this reason, change all of the bus->devices list walks in acpiphp_glue.c during which devices may be removed to be carried out in reverse order. Signed-off-by: Rafael J. Wysocki Tested-by: Mika Westerberg --- diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index cd929aed3613..6a4b4b734fbd 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -742,7 +742,7 @@ static void trim_stale_devices(struct pci_dev *dev) /* The device is a bridge. so check the bus below it. */ pm_runtime_get_sync(&dev->dev); - list_for_each_entry_safe(child, tmp, &bus->devices, bus_list) + list_for_each_entry_safe_reverse(child, tmp, &bus->devices, bus_list) trim_stale_devices(child); pm_runtime_put(&dev->dev); @@ -773,8 +773,8 @@ static void acpiphp_check_bridge(struct acpiphp_bridge *bridge) ; /* do nothing */ } else if (get_slot_status(slot) == ACPI_STA_ALL) { /* remove stale devices if any */ - list_for_each_entry_safe(dev, tmp, &bus->devices, - bus_list) + list_for_each_entry_safe_reverse(dev, tmp, + &bus->devices, bus_list) if (PCI_SLOT(dev->devfn) == slot->device) trim_stale_devices(dev); @@ -805,7 +805,7 @@ static void acpiphp_sanitize_bus(struct pci_bus *bus) int i; unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM; - list_for_each_entry_safe(dev, tmp, &bus->devices, bus_list) { + list_for_each_entry_safe_reverse(dev, tmp, &bus->devices, bus_list) { for (i=0; iresource[i]; if ((res->flags & type_mask) && !res->start &&