Commit 5dcd08cd authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller
Browse files

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: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bf955b5a

net/core/dev.c

+2 −2
Original line number Diff line number Diff line
@@ -4624,7 +4624,7 @@ static bool skb_flow_limit(struct sk_buff *skb, unsigned int qlen) 
	struct softnet_data *sd;

	unsigned int old_flow, new_flow;



	if (qlen < (netdev_max_backlog >> 1))

	if (qlen < (READ_ONCE(netdev_max_backlog) >> 1))

		return false;



	sd = this_cpu_ptr(&softnet_data);
@@ -4672,7 +4672,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu, 
	if (!netif_running(skb->dev))

		goto drop;

	qlen = skb_queue_len(&sd->input_pkt_queue);

	if (qlen <= netdev_max_backlog && !skb_flow_limit(skb, qlen)) {

	if (qlen <= READ_ONCE(netdev_max_backlog) && !skb_flow_limit(skb, qlen)) {

		if (qlen) {

enqueue:

			__skb_queue_tail(&sd->input_pkt_queue, skb);

net/core/gro_cells.c

+1 −1
Original line number Diff line number Diff line
@@ -26,7 +26,7 @@ int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb) 


	cell = this_cpu_ptr(gcells->cells);



	if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {

	if (skb_queue_len(&cell->napi_skbs) > READ_ONCE(netdev_max_backlog)) {

drop:

		dev_core_stats_rx_dropped_inc(dev);

		kfree_skb(skb);

net/xfrm/espintcp.c

+1 −1
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ int espintcp_queue_out(struct sock *sk, struct sk_buff *skb) 
{

	struct espintcp_ctx *ctx = espintcp_getctx(sk);



	if (skb_queue_len(&ctx->out_queue) >= netdev_max_backlog)

	if (skb_queue_len(&ctx->out_queue) >= READ_ONCE(netdev_max_backlog))

		return -ENOBUFS;



	__skb_queue_tail(&ctx->out_queue, skb);

net/xfrm/xfrm_input.c

+1 −1
Original line number Diff line number Diff line
@@ -782,7 +782,7 @@ int xfrm_trans_queue_net(struct net *net, struct sk_buff *skb, 


	trans = this_cpu_ptr(&xfrm_trans_tasklet);



	if (skb_queue_len(&trans->queue) >= netdev_max_backlog)

	if (skb_queue_len(&trans->queue) >= READ_ONCE(netdev_max_backlog))

		return -ENOBUFS;



	BUILD_BUG_ON(sizeof(struct xfrm_trans_cb) > sizeof(skb->cb));

Documentation/admin-guide/sysctl/net.rst

+1 −1

File changed.

Contains only whitespace changes.