[PATCH] net: filter: use DEV_STAT_INC()

[PATCH] net: filter: use DEV_STAT_INC()

[yunshui]

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,
 
 	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;
-- 
2.34.1

Re: [PATCH] net: filter: use DEV_STAT_INC()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Thu, 23 May 2024 11:35:20 +0800 you wrote:
> 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>
> 
> [...]

Here is the summary with links:
  - net: filter: use DEV_STAT_INC()
    https://git.kernel.org/bpf/bpf-next/c/d9cbd8343b01

You are awesome, thank you!
-- 
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