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>
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 3b957e6..8a7b8c7 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -3111,10 +3111,11 @@
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 @@
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;
}