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Message-ID: <87fvqznxyq.fsf@nemi.mork.no>
Date: Thu, 14 Nov 2013 10:18:05 +0100
From: Bjørn Mork <bjorn@...k.no>
To: Oliver Neukum <oliver@...kum.org>
Cc: wangbiao <biao.wang@...el.com>, netdev@...r.kernel.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
Ingo Molnar <mingo.kernel.org@...il.com>,
akpm@...ux-foundation.org, mingo@...e.hu, a.p.zijlstra@...llo.nl,
rusty@...tcorp.com.au, william.douglas@...el.com,
di.zhang@...el.com
Subject: Re: [PATCH V3] usbnet: fix race condition caused spinlock bad magic issue
Oliver Neukum <oliver@...kum.org> writes:
> On Thu, 2013-11-14 at 10:03 +0800, wangbiao wrote:
>> From: wang, biao <biao.wang@...el.com>
>> 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@...el.com>
>> Signed-off-by: Zhang, Di <di.zhang@...el.com>
> Acked-by: Oliver Neukum <oliver@...kum.org>
Really? Serializing the suspend of all usbnet devices seems like a good
idea?
Bjørn
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