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authorDongdong Deng <dongdong.deng@windriver.com>2009-08-13 23:12:31 +0400
committerDavid S. Miller <davem@davemloft.net>2009-08-15 03:41:16 +0400
commit22580f894ac190c46beebb5c3172e450a2318f79 (patch)
tree01f88df9a5bc27170ef7ca944ba40af578476d72 /drivers/net/b44.c
parent0527a1a8440a20b3d0fd1d0c9e75a6f38a9d5315 (diff)
downloadlinux-22580f894ac190c46beebb5c3172e450a2318f79.tar.xz
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/b44.c')
-rw-r--r--drivers/net/b44.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index 36d4d377ec2f..bafca672ea7d 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -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;