diff options
authorAlex Chiang <>2008-07-01 20:02:23 -0600
committerJesse Barnes <>2008-07-02 11:27:30 -0700
commita13307cef8bf51990ef1d525b1cbdcc2cfe07e2a (patch)
parent99cb233d60cbe644203f19938c729ea2bb004d70 (diff)
PCI: acpiphp: cleanup notify handler on all root bridges
During the development of the physical PCI slot patch series, Gary Hade kept on reporting strange oopses due to interactions between pci_slot and acpiphp. find_root_bridges() unconditionally installs handle_hotplug_event_bridge() as an ACPI_SYSTEM_NOTIFY handler for all root bridges. However, during module cleanup, remove_bridge() will only remove the notify handler iff the root bridge had a hot-pluggable slot directly underneath. That is: root bridge -> hotplug slot But, if the topology looks like either of the following: root bridge -> non-hotplug slot root bridge -> p2p bridge -> hotplug slot Then we currently do not remove the notify handler from that root bridge. This can cause a kernel oops if we modprobe acpiphp later and it gets loaded somewhere else in memory. If the root bridge then receives a hotplug event, it will then attempt to call a stale, non-existent notify handler and we blow up. Much thanks goes to Gary Hade for his persistent debugging efforts. Signed-off-by: Alex Chiang <> Signed-off-by: Gary Hade <> Signed-off-by: Jesse Barnes <>
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 648596d469f..91156f85a92 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -700,9 +700,10 @@ cleanup_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
cleanup_p2p_bridge, NULL, NULL);
- if (!(bridge = acpiphp_handle_to_bridge(handle)))
- return AE_OK;
- cleanup_bridge(bridge);
+ bridge = acpiphp_handle_to_bridge(handle);
+ if (bridge)
+ cleanup_bridge(bridge);
return AE_OK;
@@ -715,9 +716,19 @@ static void remove_bridge(acpi_handle handle)
acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
(u32)1, cleanup_p2p_bridge, NULL, NULL);
+ /*
+ * On root bridges with hotplug slots directly underneath (ie,
+ * no p2p bridge inbetween), we call cleanup_bridge().
+ *
+ * The else clause cleans up root bridges that either had no
+ * hotplug slots at all, or had a p2p bridge underneath.
+ */
bridge = acpiphp_handle_to_bridge(handle);
if (bridge)
+ else
+ acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
+ handle_hotplug_event_bridge);
static struct pci_dev * get_apic_pci_info(acpi_handle handle)