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authorDongdong Deng <dongdong.deng@windriver.com>2009-08-13 19:12:31 +0000
committerDavid S. Miller <davem@davemloft.net>2009-08-14 16:41:16 -0700
commit22580f894ac190c46beebb5c3172e450a2318f79 (patch)
tree01f88df9a5bc27170ef7ca944ba40af578476d72 /drivers/net/via-rhine.c
parent0527a1a8440a20b3d0fd1d0c9e75a6f38a9d5315 (diff)
downloadlinux-22580f894ac190c46beebb5c3172e450a2318f79.tar.gz
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>
Diffstat (limited to 'drivers/net/via-rhine.c')
-rw-r--r--drivers/net/via-rhine.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/via-rhine.c b/drivers/net/via-rhine.c
index 88c30a58b4bd..934f7671650a 100644
--- a/drivers/net/via-rhine.c
+++ b/drivers/net/via-rhine.c
@@ -1218,6 +1218,7 @@ static int rhine_start_tx(struct sk_buff *skb, struct net_device *dev)
 	struct rhine_private *rp = netdev_priv(dev);
 	void __iomem *ioaddr = rp->base;
 	unsigned entry;
+	unsigned long flags;
 
 	/* Caution: the write order is important here, set the field
 	   with the "ownership" bits last. */
@@ -1261,7 +1262,7 @@ static int rhine_start_tx(struct sk_buff *skb, struct net_device *dev)
 		cpu_to_le32(TXDESC | (skb->len >= ETH_ZLEN ? skb->len : ETH_ZLEN));
 
 	/* lock eth irq */
-	spin_lock_irq(&rp->lock);
+	spin_lock_irqsave(&rp->lock, flags);
 	wmb();
 	rp->tx_ring[entry].tx_status = cpu_to_le32(DescOwn);
 	wmb();
@@ -1280,7 +1281,7 @@ static int rhine_start_tx(struct sk_buff *skb, struct net_device *dev)
 
 	dev->trans_start = jiffies;
 
-	spin_unlock_irq(&rp->lock);
+	spin_unlock_irqrestore(&rp->lock, flags);
 
 	if (debug > 4) {
 		printk(KERN_DEBUG "%s: Transmit frame #%d queued in slot %d.\n",