From 4e09dcf20f7b5358615514c2ec8584b248ab8874 Mon Sep 17 00:00:00 2001
From: Huajun Li <huajun.li.lee@gmail.com>
Date: Fri, 18 May 2012 20:12:51 +0800
Subject: [PATCH] USB: Remove races in devio.c

There exist races in devio.c, below is one case,
and there are similar races in destroy_async()
and proc_unlinkurb().  Remove these races.

 cancel_bulk_urbs()        async_completed()
-------------------                -----------------------
 spin_unlock(&ps->lock);

                           list_move_tail(&as->asynclist,
		                    &ps->async_completed);

                           wake_up(&ps->wait);

                           Lead to free_async() be triggered,
                           then urb and 'as' will be freed.

 usb_unlink_urb(as->urb);
 ===> refer to the freed 'as'

Signed-off-by: Huajun Li <huajun.li.lee@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oncaphillis <oncaphillis@snafu.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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