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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.

	http://lkml.org/lkml/2007/11/28/319

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 <achiang@hp.com>
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
hifive-unleashed-5.1
Alex Chiang 2008-07-01 20:02:23 -06:00 committed by Jesse Barnes
parent 99cb233d60
commit a13307cef8
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/pci/hotplug/acpiphp_glue.c
View File

@ -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)
cleanup_bridge(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)