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ACPI / hotplug / PCI: Fix NULL pointer dereference in cleanup_bridge() 

After commit bbd34fc (ACPI / hotplug / PCI: Register all devices
under the given bridge) register_slot() is called for all PCI
devices under a given bridge that have corresponding objects in
the ACPI namespace, but it calls acpiphp_register_hotplug_slot()
only for devices satisfying specific criteria.  Still,
cleanup_bridge() calls acpiphp_unregister_hotplug_slot() for all
objects created by register_slot(), although it should only call it
for the ones that acpiphp_register_hotplug_slot() has been called
for (successfully).  This causes a NULL pointer to be dereferenced
by the acpiphp_unregister_hotplug_slot() executed by cleanup_bridge()
if the object it is called for has not been passed to
acpiphp_register_hotplug_slot().

To fix this problem, check if the 'slot' field of the object passed
to acpiphp_unregister_hotplug_slot() in cleanup_bridge() is not NULL,
which only is the case if acpiphp_register_hotplug_slot() has been
executed for that object.  In addition to that, make register_slot()
reset the 'slot' field to NULL if acpiphp_register_hotplug_slot() has
failed for the given object to prevent stale pointers from being
used by acpiphp_unregister_hotplug_slot().

Reported-and-tested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2013-08-17 22:16:33 +02:00
parent d010e5769a
commit 1aaac07112
1 changed files with 3 additions and 1 deletions
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4
drivers/pci/hotplug/acpiphp_glue.c
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@ -340,6 +340,7 @@ static acpi_status register_slot(acpi_handle handle, u32 lvl, void *data,
retval = acpiphp_register_hotplug_slot(slot, sun);
if (retval) {
slot->slot = NULL;
bridge->nr_slots--;
if (retval == -EBUSY)
warn("Slot %llu already registered by another "
@ -429,7 +430,8 @@ static void cleanup_bridge(struct acpiphp_bridge *bridge)
err("failed to remove notify handler\n");
}
}
acpiphp_unregister_hotplug_slot(slot);
if (slot->slot)
acpiphp_unregister_hotplug_slot(slot);
}
mutex_lock(&bridge_mutex);