net: Fix data-races around netdev_max_backlog.
While reading netdev_max_backlog, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.
While at it, we remove the unnecessary spaces in the doc.
Fixes: 1da177e4c3
("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
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@ -271,7 +271,7 @@ poll cycle or the number of packets processed reaches netdev_budget.
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netdev_max_backlog
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------------------
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Maximum number of packets, queued on the INPUT side, when the interface
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Maximum number of packets, queued on the INPUT side, when the interface
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receives packets faster than kernel can process them.
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netdev_rss_key
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@ -4624,7 +4624,7 @@ static bool skb_flow_limit(struct sk_buff *skb, unsigned int qlen)
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struct softnet_data *sd;
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unsigned int old_flow, new_flow;
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if (qlen < (netdev_max_backlog >> 1))
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if (qlen < (READ_ONCE(netdev_max_backlog) >> 1))
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return false;
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sd = this_cpu_ptr(&softnet_data);
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@ -4672,7 +4672,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
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if (!netif_running(skb->dev))
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goto drop;
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qlen = skb_queue_len(&sd->input_pkt_queue);
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if (qlen <= netdev_max_backlog && !skb_flow_limit(skb, qlen)) {
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if (qlen <= READ_ONCE(netdev_max_backlog) && !skb_flow_limit(skb, qlen)) {
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if (qlen) {
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enqueue:
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__skb_queue_tail(&sd->input_pkt_queue, skb);
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@ -26,7 +26,7 @@ int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
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cell = this_cpu_ptr(gcells->cells);
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if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
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if (skb_queue_len(&cell->napi_skbs) > READ_ONCE(netdev_max_backlog)) {
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drop:
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dev_core_stats_rx_dropped_inc(dev);
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kfree_skb(skb);
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@ -168,7 +168,7 @@ int espintcp_queue_out(struct sock *sk, struct sk_buff *skb)
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{
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struct espintcp_ctx *ctx = espintcp_getctx(sk);
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if (skb_queue_len(&ctx->out_queue) >= netdev_max_backlog)
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if (skb_queue_len(&ctx->out_queue) >= READ_ONCE(netdev_max_backlog))
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return -ENOBUFS;
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__skb_queue_tail(&ctx->out_queue, skb);
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@ -782,7 +782,7 @@ int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb,
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trans = this_cpu_ptr(&xfrm_trans_tasklet);
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if (skb_queue_len(&trans->queue) >= netdev_max_backlog)
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if (skb_queue_len(&trans->queue) >= READ_ONCE(netdev_max_backlog))
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return -ENOBUFS;
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BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));
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