Commit 22580f89 authored by Dongdong Deng's avatar Dongdong Deng Committed by David S. Miller
Browse files

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: default avatarDongdong Deng <dongdong.deng@windriver.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Acked-by: default avatarBruce Ashfield <bruce.ashfield@windriver.com>
Acked-by: default avatarMatt Mackall <mpm@selenic.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0527a1a8
......@@ -952,9 +952,10 @@ static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
int rc = NETDEV_TX_OK;
dma_addr_t mapping;
u32 len, entry, ctrl;
unsigned long flags;
len = skb->len;
spin_lock_irq(&bp->lock);
spin_lock_irqsave(&bp->lock, flags);
/* This is a hard error, log it. */
if (unlikely(TX_BUFFS_AVAIL(bp) < 1)) {
......@@ -1027,7 +1028,7 @@ static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
dev->trans_start = jiffies;
out_unlock:
spin_unlock_irq(&bp->lock);
spin_unlock_irqrestore(&bp->lock, flags);
return rc;
......
......@@ -652,8 +652,9 @@ tulip_start_xmit(struct sk_buff *skb, struct net_device *dev)
int entry;
u32 flag;
dma_addr_t mapping;
unsigned long flags;
spin_lock_irq(&tp->lock);
spin_lock_irqsave(&tp->lock, flags);
/* Calculate the next Tx descriptor entry. */
entry = tp->cur_tx % TX_RING_SIZE;
......@@ -688,7 +689,7 @@ tulip_start_xmit(struct sk_buff *skb, struct net_device *dev)
/* Trigger an immediate transmit demand. */
iowrite32(0, tp->base_addr + CSR1);
spin_unlock_irq(&tp->lock);
spin_unlock_irqrestore(&tp->lock, flags);
dev->trans_start = jiffies;
......
......@@ -3111,10 +3111,11 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev)
u8 __iomem *bd; /* BD pointer */
u32 bd_status;
u8 txQ = 0;
unsigned long flags;
ugeth_vdbg("%s: IN", __func__);
spin_lock_irq(&ugeth->lock);
spin_lock_irqsave(&ugeth->lock, flags);
dev->stats.tx_bytes += skb->len;
......@@ -3171,7 +3172,7 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev)
uccf = ugeth->uccf;
out_be16(uccf->p_utodr, UCC_FAST_TOD);
#endif
spin_unlock_irq(&ugeth->lock);
spin_unlock_irqrestore(&ugeth->lock, flags);
return 0;
}
......
......@@ -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",
......
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