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Date: Fri, 14 Aug 2009 16:32:32 -0700 (PDT)
Message-Id: <20090814.163232.234331420.davem@davemloft.net>
To: mpm@selenic.com
Cc: Dongdong.deng@windriver.com, netdev@vger.kernel.org,
       linux-kernel@vger.kernel.org, Bruce.Ashfield@windriver.com,
       jason.wessel@windriver.com
Subject: Re: [PATCH] drivers/net: fixed drivers that support netpoll use
 ndo_start_xmit()
From: David Miller <davem@davemloft.net>
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From: Matt Mackall <mpm@selenic.com>
Date: Fri, 14 Aug 2009 10:33:39 -0500

> On Fri, 2009-08-14 at 13:12 +0800, DDD wrote:
>> The NETPOLL API requires that interrupts remain disabled in
>> netpoll_send_skb(). The use of spin_lock_irq() and spin_unlock_irq()
>> in the NETPOLL API callbacks causes the interrupts to get enabled and
>> can lead to kernel instability.
>> 
>> The solution is to use spin_lock_irqsave() and spin_unlock_restore()
>> to prevent the irqs from getting enabled while in netpoll_send_skb().
 ...
>> Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
>> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
>> Acked-by: Bruce Ashfield <bruce.ashfield@windriver.com>
> 
> Acked-by: Matt Mackall <mpm@selenic.com>

Applied, thanks everyone.

> Perhaps we should also have a WARN_ONCE if start_xmit returns with
> interrupts enabled?

Probably a good idea.