Commit d9cbd834 authored by yunshui's avatar yunshui Committed by Daniel Borkmann
Browse files

bpf, net: Use DEV_STAT_INC() 



syzbot/KCSAN reported that races happen when multiple CPUs updating
dev->stats.tx_error concurrently. Adopt SMP safe DEV_STATS_INC() to
update the dev->stats fields.

Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
Signed-off-by: default avataryunshui <jiangyunshui@kylinos.cn>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240523033520.4029314-1-jiangyunshui@kylinos.cn
parent e245ef8a

net/core/filter.c

+4 −4
Original line number Diff line number Diff line
@@ -2274,12 +2274,12 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev, 


	err = bpf_out_neigh_v6(net, skb, dev, nh);

	if (unlikely(net_xmit_eval(err)))

		dev->stats.tx_errors++;

		DEV_STATS_INC(dev, tx_errors);

	else

		ret = NET_XMIT_SUCCESS;

	goto out_xmit;

out_drop:

	dev->stats.tx_errors++;

	DEV_STATS_INC(dev, tx_errors);

	kfree_skb(skb);

out_xmit:

	return ret;
@@ -2380,12 +2380,12 @@ static int __bpf_redirect_neigh_v4(struct sk_buff *skb, struct net_device *dev, 


	err = bpf_out_neigh_v4(net, skb, dev, nh);

	if (unlikely(net_xmit_eval(err)))

		dev->stats.tx_errors++;

		DEV_STATS_INC(dev, tx_errors);

	else

		ret = NET_XMIT_SUCCESS;

	goto out_xmit;

out_drop:

	dev->stats.tx_errors++;

	DEV_STATS_INC(dev, tx_errors);

	kfree_skb(skb);

out_xmit:

	return ret;