Re: [PATCH V3] usbnet: fix race condition caused spinlock badmagic issue

[Oliver Neukum]

On Thu, 2013-11-14 at 10:03 +0800, wangbiao wrote:
> From: wang, biao <biao.wang@xxxxxxxxx>
> Date: Mon, 11 Nov 2013 10:23:40 +0800
> Subject: [PATCH] usbnet: fix race condition caused spinlock bad magic issue
> 
> there is race between usbnet_terminate_urbs and usbnet_bh.
> for example:
>     cpu 0                                     cpu 1
>                                           usbnet_suspend
> usbnet_bh {                               ->usbnet_terminate_urbs {
>                                               dev->wait = &unlink_wakeup;
>                                               while(....){..}//break
>     if(dev->wait) is true
>                        		              dev->wait=NULL
>                                           }//unlink_wakeup is invalid
>     __wake_up(dev->wait)//garbage value
> }
> 
> the race is due to unprotection of dev->wait, so this patch involves a
> spinlock to avoid it.
> 
> Signed-off-by: wang, biao <biao.wang@xxxxxxxxx>
> Signed-off-by: Zhang, Di <di.zhang@xxxxxxxxx>
Acked-by: Oliver Neukum <oliver@xxxxxxxxxx>

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