Commit 1c20e37c authored by Joe Lawrence's avatar Joe Lawrence Committed by Ben Hutchings

usb: hub: take hub->hdev reference when processing from eventlist

commit c605f3cd upstream.

During surprise device hotplug removal tests, it was observed that
hub_events may try to call usb_lock_device on a device that has already
been freed. Protect the usb_device by taking out a reference (under the
hub_event_lock) when hub_events pulls it off the list, returning the
reference after hub_events is finished using it.
Signed-off-by: default avatarJoe Lawrence <joe.lawrence@stratus.com>
Suggested-by: David Bulkow <david.bulkow@stratus.com> for using kref
Suggested-by: Alan Stern <stern@rowland.harvard.edu> for placement
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 9a91e2d1
......@@ -3651,9 +3651,10 @@ static void hub_events(void)
hub = list_entry(tmp, struct usb_hub, event_list);
kref_get(&hub->kref);
hdev = hub->hdev;
usb_get_dev(hdev);
spin_unlock_irq(&hub_event_lock);
hdev = hub->hdev;
hub_dev = hub->intfdev;
intf = to_usb_interface(hub_dev);
dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
......@@ -3888,6 +3889,7 @@ static void hub_events(void)
usb_autopm_put_interface(intf);
loop_disconnected:
usb_unlock_device(hdev);
usb_put_dev(hdev);
kref_put(&hub->kref, hub_release);
} /* end while (1) */
......
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