From c605f3cdff53a743f6d875b76956b239deca1272 Mon Sep 17 00:00:00 2001 From: Joe Lawrence Date: Wed, 10 Sep 2014 15:07:50 -0400 Subject: [PATCH] usb: hub: take hub->hdev reference when processing from eventlist 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 Suggested-by: David Bulkow for using kref Suggested-by: Alan Stern for placement Acked-by: Alan Stern Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 46f5161c7891..d481c99a20d7 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -5024,9 +5024,10 @@ 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", @@ -5139,6 +5140,7 @@ 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) */ -- 2.20.1