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>
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