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authorAlex Chiang <achiang@hp.com>2009-03-30 10:50:19 -0600
committerJesse Barnes <jbarnes@virtuousgeek.org>2009-04-06 11:31:14 -0700
commit72800360fdd782eda3489e555adf3b6b3abc064a (patch)
treef71284f4081b7b321a0e592f18bdd4b571bf5164 /drivers/acpi/pci_slot.c
parent5d4a4b25ddc3e864d3a562c024bebdc922118854 (diff)
downloadlwn-72800360fdd782eda3489e555adf3b6b3abc064a.tar.gz
lwn-72800360fdd782eda3489e555adf3b6b3abc064a.zip
PCI: pci_slot: grab refcount on slot's bus
If a logical hot unplug (remove) is performed on a physical PCI slot's parent bridge, and then pci_slot is unloaded, we will encounter an oops: [<ffffffff803a788a>] kobject_release+0x9a/0x290 [<ffffffff803a77f0>] ? kobject_release+0x0/0x290 [<ffffffff803a8ce7>] kref_put+0x37/0x80 [<ffffffff803a76f7>] kobject_put+0x27/0x60 [<ffffffff803bebcc>] ? pci_destroy_slot+0x3c/0xc0 [<ffffffff803bebd5>] pci_destroy_slot+0x45/0xc0 [<ffffffffa000f05c>] acpi_pci_slot_remove+0x5c/0x91 [pci_slot] [<ffffffff8040064b>] acpi_pci_unregister_driver+0x4b/0x62 [<ffffffffa000f5c8>] acpi_pci_slot_exit+0x10/0x12 [pci_slot] [<ffffffff80276ce1>] sys_delete_module+0x161/0x250 We need to grab a reference to the parent PCI bus, which will pin the bus and prevent it from being released until pci_slot is unloaded. Cc: lenb@kernel.org Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/acpi/pci_slot.c')
-rw-r--r--drivers/acpi/pci_slot.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/acpi/pci_slot.c b/drivers/acpi/pci_slot.c
index cd1f4467be7b..12158e0d009b 100644
--- a/drivers/acpi/pci_slot.c
+++ b/drivers/acpi/pci_slot.c
@@ -164,6 +164,8 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
list_add(&slot->list, &slot_list);
mutex_unlock(&slot_list_lock);
+ get_device(&pci_bus->dev);
+
dbg("pci_slot: %p, pci_bus: %x, device: %d, name: %s\n",
pci_slot, pci_bus->number, device, name);
@@ -310,12 +312,15 @@ static void
acpi_pci_slot_remove(acpi_handle handle)
{
struct acpi_pci_slot *slot, *tmp;
+ struct pci_bus *pbus;
mutex_lock(&slot_list_lock);
list_for_each_entry_safe(slot, tmp, &slot_list, list) {
if (slot->root_handle == handle) {
list_del(&slot->list);
+ pbus = slot->pci_slot->bus;
pci_destroy_slot(slot->pci_slot);
+ put_device(&pbus->dev);
kfree(slot);
}
}