Commit 95e48d86 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: enqueue_to_backlog() change vs not running device 



If the device attached to the packet given to enqueue_to_backlog()
is not running, we drop the packet.

But we accidentally increase sd->dropped, giving false signals
to admins: sd->dropped should be reserved to cpu backlog pressure,
not to temporary glitches at device dismantles.

While we are at it, perform the netif_running() test before
we get the rps lock, and use REASON_DEV_READY
drop reason instead of NOT_SPECIFIED.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2fe50a4d

net/core/dev.c

+5 −4
Original line number Diff line number Diff line
@@ -4801,12 +4801,13 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, 
	unsigned long flags;

	unsigned int qlen;



	reason = SKB_DROP_REASON_NOT_SPECIFIED;

	reason = SKB_DROP_REASON_DEV_READY;

	if (!netif_running(skb->dev))

		goto bad_dev;



	sd = &per_cpu(softnet_data, cpu);



	backlog_lock_irq_save(sd, &flags);

	if (!netif_running(skb->dev))

		goto drop;

	qlen = skb_queue_len(&sd->input_pkt_queue);

	if (qlen <= READ_ONCE(net_hotdata.max_backlog) &&

	    !skb_flow_limit(skb, qlen)) {
@@ -4827,10 +4828,10 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, 
	}

	reason = SKB_DROP_REASON_CPU_BACKLOG;



drop:

	sd->dropped++;

	backlog_unlock_irq_restore(sd, &flags);



bad_dev:

	dev_core_stats_rx_dropped_inc(skb->dev);

	kfree_skb_reason(skb, reason);

	return NET_RX_DROP;