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From: yunshui <jiangyunshui@kylinos.cn>
To: bpf@vger.kernel.org,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: martin.lau@linux.dev,
	daniel@iogearbox.net,
	john.fastabend@gmail.com,
	edumazet@google.com,
	yunshui <jiangyunshui@kylinos.cn>,
	syzbot <syzkaller@googlegroups.com>
Subject: [PATCH] net: filter: use DEV_STAT_INC()
Date: Thu, 23 May 2024 11:35:20 +0800
Message-Id: <20240523033520.4029314-1-jiangyunshui@kylinos.cn>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable

syzbot/KCSAN reported that races happen when multiple cpus
updating dev->stats.tx_error concurrently.

Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: yunshui <jiangyunshui@kylinos.cn>
---
 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 2510464692af..9968db21a29d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2274,12 +2274,12 @@ static int __bpf_redirect_neigh_v6(struct sk_buff=
 *skb, struct net_device *dev,
=20
 	err =3D 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 =3D 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,
=20
 	err =3D 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 =3D 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;
--=20
2.34.1