[PATCH 8/16][BUG] PCI slot: Fix invalid memory access (Not for mainline!)

Kenji Kaneshige
2008-03-21T04:20:09Z

Fix kernel oops in pci_release_slot() when dbg() is enabled.

The dbg() in pci_release_slot() cause a kernel oops (invalid memory
access) because it accesses slot after it is released. We need to
access slot before calling kobject_put().

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

---
drivers/pci/slot.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

Index: linux-2.6.25-rc6/drivers/pci/slot.c
===================================================================
--- linux-2.6.25-rc6.orig/drivers/pci/slot.c
+++ linux-2.6.25-rc6/drivers/pci/slot.c
@@ -191,13 +191,14 @@ EXPORT_SYMBOL_GPL(pci_create_slot);

int pci_destroy_slot(struct pci_slot *slot)
{
+ dbg("%s: decreased refcount to %d on %x:%d\n", __func__,
+ atomic_read(&slot->kobj.kref.refcount) - 1, slot->bus->number,
+ slot->number);
+
down_write(&pci_bus_sem);
kobject_put(&slot->kobj);
up_write(&pci_bus_sem);

- dbg("%s: decreased refcount to %d on %x:%d\n", __func__,
- atomic_read(&slot->kobj.kref.refcount), slot->bus->number,
- slot->number);
return 0;
}
EXPORT_SYMBOL_GPL(pci_destroy_slot);