| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 096/238] usb: hub: take hub->hdev reference when processing from eventlist | Date | Fri, 3 Oct 2014 14:30:11 -0700 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Joe Lawrence <joe.lawrence@stratus.com>
commit c605f3cdff53a743f6d875b76956b239deca1272 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: Joe 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: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/usb/core/hub.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4764,9 +4764,10 @@ 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", @@ -4979,6 +4980,7 @@ 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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