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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-01-14 12:04:51 -0700
committerBjorn Helgaas <bhelgaas@google.com>2014-01-15 10:34:13 -0700
commit8a4c5c329de716996eea03d93753ccbb5406072b (patch)
tree4a9c74354b7f7bbb39ae0426246d4b9baff3cc7f /drivers/pci
parenta83919e0940f6eb8f77ab1d602a063f8a6703117 (diff)
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PCI: Check parent kobject in pci_destroy_dev()
If pci_stop_and_remove_bus_device() is run concurrently for a device and its parent bridge via remove_callback(), both code paths attempt to acquire pci_rescan_remove_lock. If the child device removal acquires it first, there will be no problems. However, if the parent bridge removal acquires it first, it will eventually execute pci_destroy_dev() for the child device, but that device object will not be freed yet due to the reference held by the concurrent child removal. Consequently, both pci_stop_bus_device() and pci_remove_bus_device() will be executed for that device unnecessarily and pci_destroy_dev() will see a corrupted list head in that object. Moreover, an excess put_device() will be executed for that device in that case which may lead to a use-after-free in the final kobject_put() done by sysfs_schedule_callback_work(). To avoid that problem, make pci_destroy_dev() check if the device's parent kobject is NULL, which only happens after device_del() has already run for it. Make pci_destroy_dev() return immediately whithout doing anything in that case. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/remove.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 10fa13f9e309..4ff36bfa785e 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -20,6 +20,9 @@ static void pci_stop_dev(struct pci_dev *dev)
static void pci_destroy_dev(struct pci_dev *dev)
{
+ if (!dev->dev.kobj.parent)
+ return;
+
device_del(&dev->dev);
put_device(&dev->dev);