From: Dongdong Deng <dongdong.deng@windriver.com>
Date: Thu, 13 Aug 2009 19:12:31 +0000 (+0000)
Subject: drivers/net: fixed drivers that support netpoll use ndo_start_xmit()
X-Git-Tag: v2.6.31-rc7~27^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=22580f894ac190c46beebb5c3172e450a2318f79;p=pandora-kernel.git

drivers/net: fixed drivers that support netpoll use ndo_start_xmit()

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().

Call trace:
netpoll_send_skb()
{
   -> local_irq_save(flags)
     ---> dev->ndo_start_xmit(skb, dev)
         ---> spin_lock_irq()
         ---> spin_unlock_irq() *******here would enable the interrupt.
              ...
   -> local_irq_restore(flags)
}

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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