net/packet: tpacket_rcv: do not increment ring index on drop (46e4c421) · Commits · 戴 / test

In one error case, tpacket_rcv drops packets after incrementing the ring producer index. If this happens, it does not update tp_status to TP_STATUS_USER and thus the reader is stalled for an iteration of the ring, causing out of order arrival. The only such error path is when virtio_net_hdr_from_skb fails due to encountering an unknown GSO type. Signed-off-by:

Willem de Bruijn <willemb@google.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/packet/af_packet.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -2274,6 +2274,13 @@ static int tpacket_rcv(struct sk_buff skb, struct net_device dev,
		TP_STATUS_KERNEL, (macoff+snaplen));
		if (!h.raw)
		goto drop_n_account;

		if (do_vnet &&
		virtio_net_hdr_from_skb(skb, h.raw + macoff -
		sizeof(struct virtio_net_hdr),
		vio_le(), true, 0))
		goto drop_n_account;

		if (po->tp_version <= TPACKET_V2) {
		packet_increment_rx_head(po, &po->rx_ring);
		/*
		@@ -2286,12 +2293,6 @@ static int tpacket_rcv(struct sk_buff skb, struct net_device dev,
		status \|= TP_STATUS_LOSING;
		}

		if (do_vnet &&
		virtio_net_hdr_from_skb(skb, h.raw + macoff -
		sizeof(struct virtio_net_hdr),
		vio_le(), true, 0))
		goto drop_n_account;

		po->stats.stats1.tp_packets++;
		if (copy_skb) {
		status \|= TP_STATUS_COPY;

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