[PATCH net] net: veth: fix ethtool stats reporting

[PATCH net] net: veth: fix ethtool stats reporting

[Lorenzo Bianconi]

Fix a possible misalignment between page_pool stats and tx xdp_stats
reported in veth_get_ethtool_stats routine.
The issue can be reproduced configuring the veth pair with the
following tx/rx queues:

$ip link add v0 numtxqueues 2 numrxqueues 4 type veth peer name v1 \
 numtxqueues 1 numrxqueues 1

and loading a simple XDP program on v0 that just returns XDP_PASS.
In this case on v0 the page_pool stats overwrites tx xdp_stats for queue 1.
Fix the issue incrementing pp_idx of dev->real_num_tx_queues * VETH_TQ_STATS_LEN
since we always report xdp_stats for all tx queues in ethtool.

Fixes: 4fc418053ec7 ("net: veth: add page_pool stats")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/veth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 9980517ed8b0..8607eb8cf458 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -236,8 +236,8 @@ static void veth_get_ethtool_stats(struct net_device *dev,
 				data[tx_idx + j] += *(u64 *)(base + offset);
 			}
 		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
-		pp_idx = tx_idx + VETH_TQ_STATS_LEN;
 	}
+	pp_idx = idx + dev->real_num_tx_queues * VETH_TQ_STATS_LEN;
 
 page_pool_stats:
 	veth_get_page_pool_stats(dev, &data[pp_idx]);
-- 
2.42.0

Re: [PATCH net] net: veth: fix ethtool stats reporting

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Tue, 21 Nov 2023 20:08:44 +0100 you wrote:
> Fix a possible misalignment between page_pool stats and tx xdp_stats
> reported in veth_get_ethtool_stats routine.
> The issue can be reproduced configuring the veth pair with the
> following tx/rx queues:
> 
> $ip link add v0 numtxqueues 2 numrxqueues 4 type veth peer name v1 \
>  numtxqueues 1 numrxqueues 1
> 
> [...]

Here is the summary with links:
  - [net] net: veth: fix ethtool stats reporting
    https://git.kernel.org/netdev/net/c/818ad9cc90d4

You are awesome, thank you!
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