[PATCH] PCI: fix race with pci_walk_bus and pci_destroy_dev
pci_walk_bus has a race with pci_destroy_dev. When cb is called
in pci_walk_bus, pci_destroy_dev might unlink the dev pointed by next.
Later on in the next loop, pointer next becomes NULL and cause
kernel panic.
Below patch against 2.6.17-rc4 fixes it by changing pci_bus_lock (spin_lock)
to pci_bus_sem (rw_semaphore).
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 1a6bf9d..99ffbd4 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -22,18 +22,18 @@
pci_proc_detach_device(dev);
pci_remove_sysfs_dev_files(dev);
device_unregister(&dev->dev);
- spin_lock(&pci_bus_lock);
+ down_write(&pci_bus_sem);
list_del(&dev->global_list);
dev->global_list.next = dev->global_list.prev = NULL;
- spin_unlock(&pci_bus_lock);
+ up_write(&pci_bus_sem);
}
/* Remove the device from the device lists, and prevent any further
* list accesses from this device */
- spin_lock(&pci_bus_lock);
+ down_write(&pci_bus_sem);
list_del(&dev->bus_list);
dev->bus_list.next = dev->bus_list.prev = NULL;
- spin_unlock(&pci_bus_lock);
+ up_write(&pci_bus_sem);
pci_free_resources(dev);
pci_dev_put(dev);
@@ -62,9 +62,9 @@
{
pci_proc_detach_bus(pci_bus);
- spin_lock(&pci_bus_lock);
+ down_write(&pci_bus_sem);
list_del(&pci_bus->node);
- spin_unlock(&pci_bus_lock);
+ up_write(&pci_bus_sem);
pci_remove_legacy_files(pci_bus);
class_device_remove_file(&pci_bus->class_dev,
&class_device_attr_cpuaffinity);