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authorArjan van de Ven <arjan@infradead.org>2006-07-05 15:00:40 +0200
committerJeff Garzik <jeff@garzik.org>2006-07-05 14:29:26 -0400
commitbce305f4fe779f29d99d414685243f5da0803254 (patch)
tree67072c37319f3c6b091dec8094d342118fe3fd62 /drivers/net/8139too.c
parent20ed7c094dfe33b0e15e8c60f60012b9278631d3 (diff)
[PATCH] 8139too deadlock fix
> stack backtrace: > [<f9099d31>] rtl8139_start_xmit+0xd9/0xff [8139too] > [<c11ad5ea>] netpoll_send_skb+0x98/0xea This seems to be a real deadlock... So netpoll_send_skb takes the _xmit_lock, which is all nitty gritty but then rtl8139_start_xmit comes around while that lock is taken, and does spin_unlock_irq(&tp->lock); which.. enables interrupts and softirqs; this is quite bad because the xmit lock is taken in softirq context for the watchdog like this: [<c1200376>] _spin_lock+0x23/0x32 [<c11af282>] dev_watchdog+0x14/0xb1 [<c101dab2>] run_timer_softirq+0xf2/0x14a [<c101a691>] __do_softirq+0x55/0xb0 [<c1004a8d>] do_softirq+0x58/0xbd Which would deadlock now that the spin_unlock_irq() has enabled irqs/softirqs while the _xmit_lock is still held. The patch below turns this into a irqsave/irqrestore pair so that interrupts don't get enabled unconditionally. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'drivers/net/8139too.c')
-rw-r--r--drivers/net/8139too.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/8139too.c b/drivers/net/8139too.c
index cd9718512d1..e4f4eaff767 100644
--- a/drivers/net/8139too.c
+++ b/drivers/net/8139too.c
@@ -1709,6 +1709,7 @@ static int rtl8139_start_xmit (struct sk_buff *skb, struct net_device *dev)
void __iomem *ioaddr = tp->mmio_addr;
unsigned int entry;
unsigned int len = skb->len;
+ unsigned long flags;
/* Calculate the next Tx descriptor entry. */
entry = tp->cur_tx % NUM_TX_DESC;
@@ -1725,7 +1726,7 @@ static int rtl8139_start_xmit (struct sk_buff *skb, struct net_device *dev)
return 0;
}
- spin_lock_irq(&tp->lock);
+ spin_lock_irqsave(&tp->lock, flags);
RTL_W32_F (TxStatus0 + (entry * sizeof (u32)),
tp->tx_flag | max(len, (unsigned int)ETH_ZLEN));
@@ -1736,7 +1737,7 @@ static int rtl8139_start_xmit (struct sk_buff *skb, struct net_device *dev)
if ((tp->cur_tx - NUM_TX_DESC) == tp->dirty_tx)
netif_stop_queue (dev);
- spin_unlock_irq(&tp->lock);
+ spin_unlock_irqrestore(&tp->lock, flags);
if (netif_msg_tx_queued(tp))
printk (KERN_DEBUG "%s: Queued Tx packet size %u to slot %d.\n",