From: Alan Stern <st...@rowland.harvard.edu>

This patch (as1476) fixes a regression introduced by
fccf4e86200b8f5edd9a65da26f150e32ba79808 (USB: Free bandwidth when
usb_disable_device is called).  usb_disconnect() grabs the
bandwidth_mutex before calling usb_disable_device(), which calls down
indirectly to usb_set_interface(), which tries to acquire the
bandwidth_mutex.

The fix causes usb_set_interface() to return early when it is called
for an interface that has already been unregistered, which is what
happens in usb_disable_device().

Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
Tested-by: Sarah Sharp <sarah.a.sh...@linux.intel.com>
Cc: stable <sta...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@suse.de>
---
 drivers/usb/core/message.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 64c7ab4..e0719b4 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1286,6 +1286,8 @@ int usb_set_interface(struct usb_device *dev, int 
interface, int alternate)
                        interface);
                return -EINVAL;
        }
+       if (iface->unregistering)
+               return -ENODEV;
 
        alt = usb_altnum_to_altsetting(iface, alternate);
        if (!alt) {
-- 
1.7.6

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