Le lundi 30 janvier 2012 à 11:14 +0100, Eric Dumazet a écrit :
> Le lundi 30 janvier 2012 à 12:51 +0300, Denis Kirjanov a écrit :
> > I'll check this out. After kernel.org was cracked I've missed
> > @kernel.org mail account.
> 
> 
> At first glance, start_tx() is racy against TX completion.
> 
> It does :
> 
>         if (np->cur_tx - np->dirty_tx < TX_QUEUE_LEN - 1 &&
>             !netif_queue_stopped(dev)) {
>                 /* do nothing */
>         } else {
>                 netif_stop_queue (dev);
>         }
> 
> So it can call netif_stop_queue() while TX completion handler did a
> cleanup of all queued packets right before.
> 
> 
> Note intr_handler() doesnt hold the queue spinlock when it does :
> 
>                 if (netif_queue_stopped(dev) &&
>                         np->cur_tx - np->dirty_tx < TX_QUEUE_LEN - 4) {
>                         /* The ring is no longer full, clear busy flag. */
>                         netif_wake_queue (dev);
>                 }
> 

So I would try following patch :

 drivers/net/ethernet/dlink/sundance.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/dlink/sundance.c 
b/drivers/net/ethernet/dlink/sundance.c
index 28a3a9b..c671a6c 100644
--- a/drivers/net/ethernet/dlink/sundance.c
+++ b/drivers/net/ethernet/dlink/sundance.c
@@ -1099,11 +1099,13 @@ start_tx (struct sk_buff *skb, struct net_device *dev)
        tasklet_schedule(&np->tx_tasklet);
 
        /* On some architectures: explicitly flush cache lines here. */
-       if (np->cur_tx - np->dirty_tx < TX_QUEUE_LEN - 1 &&
-           !netif_queue_stopped(dev)) {
-               /* do nothing */
-       } else {
-               netif_stop_queue (dev);
+       if (np->cur_tx - np->dirty_tx >= TX_QUEUE_LEN - 1) {
+               unsigned long flags;
+
+               spin_lock_irqsave(&np->lock, flags);
+               if (np->cur_tx - np->dirty_tx >= TX_QUEUE_LEN - 1)
+                       netif_stop_queue(dev);
+               spin_unlock_irqrestore(&np->lock, flags);
        }
        if (netif_msg_tx_queued(np)) {
                printk (KERN_DEBUG





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