From fdf3f6800be36377e045e2448087f12132b88d2f Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Thu, 29 Jan 2026 19:38:27 -0800 Subject: [PATCH] net: don't touch dev->stats in BPF redirect paths Gal reports that BPF redirect increments dev->stats.tx_errors on failure. This is not correct, most modern drivers completely ignore dev->stats so these drops will be invisible to the user. Core code should use the dedicated core stats which are folded into device stats in dev_get_stats(). Note that we're switching from tx_errors to tx_dropped. Core only has tx_dropped, hence presumably users already expect that counter to increment for "stack" Tx issues. Reported-by: Gal Pressman Link: https://lore.kernel.org/c5df3b60-246a-4030-9c9a-0a35cd1ca924@nvidia.com Fixes: b4ab31414970 ("bpf: Add redirect_neigh helper as redirect drop-in") Acked-by: Martin KaFai Lau Acked-by: Daniel Borkmann Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260130033827.698841-1-kuba@kernel.org Signed-off-by: Jakub Kicinski --- net/core/filter.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index bcd73d9bd764..029e560e32ce 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2289,12 +2289,12 @@ 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_INC(dev, tx_errors); + dev_core_stats_tx_dropped_inc(dev); else ret = NET_XMIT_SUCCESS; goto out_xmit; out_drop: - DEV_STATS_INC(dev, tx_errors); + dev_core_stats_tx_dropped_inc(dev); kfree_skb(skb); out_xmit: return ret; @@ -2396,12 +2396,12 @@ 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_INC(dev, tx_errors); + dev_core_stats_tx_dropped_inc(dev); else ret = NET_XMIT_SUCCESS; goto out_xmit; out_drop: - DEV_STATS_INC(dev, tx_errors); + dev_core_stats_tx_dropped_inc(dev); kfree_skb(skb); out_xmit: return ret; -- 2.47.3