From nobody Fri Feb 13 22:39:36 2026 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAC5813849C for ; Mon, 20 May 2024 23:59:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716249550; cv=none; b=WGQAYr/ZYABRQwG2XHEOJD+A7n1jiZqmXyZ2wUdxfZ5IbSMx9MnVYZUrh/j0hNgCvu5xYN5uY83hunPjv1zz3Y8qgO/Aj8kPcHMACvR8JtcpXTdRSZu7Q3SrZNvTFMeZWNEMc7cNZgOrxJ9o8JuxHExTZJlq94QoBOdnNw675lA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716249550; c=relaxed/simple; bh=xiGzFz5+hu1xpjpEUf4HSER5PouTUhVlGDQbTva3RGc=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=h6M3sBvnnbBVK/1e6Jlg41WQNNIY+VbUpB2IIyUyI1uqFPkNxBoTwZMSDpeIv6JDKciicaETsy996utQtIxdKR02wjMBAHlopMhoL+6Kx3lZA2XlSzHKUl2oJPtGz5NzHhg9zyyr78c6iPyYXQ+C/AqhI3s50oVUWPtbYKBkPzg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com; spf=pass smtp.mailfrom=fastly.com; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b=gkMkTpuo; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=fastly.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fastly.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=fastly.com header.i=@fastly.com header.b="gkMkTpuo" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-1edf506b216so88179525ad.2 for ; Mon, 20 May 2024 16:59:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fastly.com; s=google; t=1716249548; x=1716854348; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=4MSMZDcDirakrNTBU0fNIxBAtvPtCqIO/PWdx7abHpI=; b=gkMkTpuodemqcggQX+QS8j0l5j69KRlVLl/ZYmtwb+jylUbVhpJAYPDwzBAiMbv0kK M1mBQHqmg5/XNBvKwFVPPwvw2omyLT0NWme67XFACTm1V7P9WWOJJ4bim4M4I4APfk7m 25q97hqUuUqKSWtajbFFdBUFkM56qr7ObCE6M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716249548; x=1716854348; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=4MSMZDcDirakrNTBU0fNIxBAtvPtCqIO/PWdx7abHpI=; b=vDl0TwsHL4DzuQ1IfxOtENHmTgTjoFzCkJ/atP4SBoo/kmZFwDJyEcKWp8CTQ4dc2S lxawIrvrWESip46/djiCCcMaYtKQS6aYQ+Ry20leBzmcLhm5XKUnLkQ+37tx3drpDRyW O7qSM2jm0Ap+FbuM74T/z0nu8IajmlRpzBNEADJsXcMsTbxYSd01gLOMTdR8yIotIXtQ ZfbeX8cTLbgWHGxuhfRplGdaEHsWZJg+jxJCHkptZt5fYZf+uXT6FiyN/N/PTfXuwk+x 3LlhCb4DG6AwWL66a/ElS3/QlU4rfa7/9A1QHP1XSHSopdSU4FkNrtj7kEFOM6tBIU3q Sl2g== X-Gm-Message-State: AOJu0YzzBOaOD9zj4InFv2tgHOU96u7RnO7ClNtHOeQZq16YU1GEWZ7j tnqFHA3lzQB1aMUjMskiu9wS7fLbiEK6Pvp2bKi9csx6aLKreBn7N//l54TkjShcsTlcCl4QxT5 i/3c/N7Sw5IVe85o6spiK7/lVw6jATqpCkseJnud96IaH2NC1v5VYg6qJbMzlx56hwoPQ9H7PKz WzdgXcoSvyUKZdhPUQk7ayQRtFM7DXAUYgDu/MiJiQn/0= X-Google-Smtp-Source: AGHT+IEU8qMZMI8smQVTlaGJaOblB8+OFUaGoNtT7FdaCarnHSQtmXoufAf+oYRHDz0WoQmCt8OpTA== X-Received: by 2002:a05:6a20:96d2:b0:1af:d07a:37c8 with SMTP id adf61e73a8af0-1afde128be9mr28414750637.37.1716249547566; Mon, 20 May 2024 16:59:07 -0700 (PDT) Received: from localhost.localdomain ([2620:11a:c019:0:65e:3115:2f58:c5fd]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-6f66e4a24f4sm11111009b3a.0.2024.05.20.16.59.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 May 2024 16:59:07 -0700 (PDT) From: Joe Damato To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: nalramli@fastly.com, Joe Damato , Shuah Khan , Jakub Kicinski , "David S. Miller" , linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST FRAMEWORK) Subject: [PATCH net] testing: net-drv: use stats64 for testing Date: Mon, 20 May 2024 23:58:43 +0000 Message-Id: <20240520235850.190041-1-jdamato@fastly.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Testing a network device that has large numbers of bytes/packets may overflow. Using stats64 when comparing fixes this problem. I tripped on this while iterating on a qstats patch for mlx5. See below for confirmation without my added code that this is a bug. Before this patch (with added debugging output): $ NETIF=3Deth0 tools/testing/selftests/drivers/net/stats.py KTAP version 1 1..4 ok 1 stats.check_pause ok 2 stats.check_fec rstat: 481708634 qstat: 666201639514 key: tx-bytes not ok 3 stats.pkt_byte_sum ok 4 stats.qstat_by_ifindex Note the huge delta above ^^^ in the rtnl vs qstats. After this patch: $ NETIF=3Deth0 tools/testing/selftests/drivers/net/stats.py KTAP version 1 1..4 ok 1 stats.check_pause ok 2 stats.check_fec ok 3 stats.pkt_byte_sum ok 4 stats.qstat_by_ifindex It looks like rtnl_fill_stats in net/core/rtnetlink.c will attempt to copy the 64bit stats into a 32bit structure which is probably why this behavior is occurring. To show this is happening, you can get the underlying stats that the stats.py test uses like this: $ ./cli.py --spec ../../../Documentation/netlink/specs/rt_link.yaml \ --do getlink --json '{"ifi-index": 7}' And examine the output (heavily snipped to show relevant fields): 'stats': { 'multicast': 3739197, 'rx-bytes': 1201525399, 'rx-packets': 56807158, 'tx-bytes': 492404458, 'tx-packets': 1200285371, 'stats64': { 'multicast': 3739197, 'rx-bytes': 35561263767, 'rx-packets': 56807158, 'tx-bytes': 666212335338, 'tx-packets': 1200285371, The stats.py test prior to this patch was using the 'stats' structure above, which matches the failure output on my system. Comparing side by side, rx-bytes and tx-bytes, and getting ethtool -S output: rx-bytes stats: 1201525399 rx-bytes stats64: 35561263767 rx-bytes ethtool: 36203402638 tx-bytes stats: 492404458 tx-bytes stats64: 666212335338 tx-bytes ethtool: 666215360113 Note that the above was taken from a system with an mlx5 NIC, which only exposes ndo_get_stats64. Based on the ethtool output and qstat output, it appears that stats.py should be updated to use the 'stats64' structure for accurate comparisons when packet/byte counters get very large. To confirm that this was not related to the qstats code I was iterating on, I booted a kernel without my driver changes and re-ran the test which shows the qstats are skipped (as they don't exist for mlx5): NETIF=3Deth0 tools/testing/selftests/drivers/net/stats.py KTAP version 1 1..4 ok 1 stats.check_pause ok 2 stats.check_fec ok 3 stats.pkt_byte_sum # SKIP qstats not supported by the device ok 4 stats.qstat_by_ifindex # SKIP No ifindex supports qstats But, fetching the stats using the CLI $ ./cli.py --spec ../../../Documentation/netlink/specs/rt_link.yaml \ --do getlink --json '{"ifi-index": 7}' Shows the same issue (heavily snipped for relevant fields only): 'stats': { 'multicast': 105489, 'rx-bytes': 530879526, 'rx-packets': 751415, 'tx-bytes': 2510191396, 'tx-packets': 27700323, 'stats64': { 'multicast': 105489, 'rx-bytes': 530879526, 'rx-packets': 751415, 'tx-bytes': 15395093284, 'tx-packets': 27700323, Comparing side by side with ethtool -S on the unmodified mlx5 driver: tx-bytes stats: 2510191396 tx-bytes stats64: 15395093284 tx-bytes ethtool: 17718435810 Fixes: f0e6c86e4bab ("testing: net-drv: add a driver test for stats reporti= ng") Signed-off-by: Joe Damato --- tools/testing/selftests/drivers/net/stats.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/drivers/net/stats.py b/tools/testing/s= elftests/drivers/net/stats.py index 7a7b16b180e2..820b8e0a22c6 100755 --- a/tools/testing/selftests/drivers/net/stats.py +++ b/tools/testing/selftests/drivers/net/stats.py @@ -69,7 +69,7 @@ def pkt_byte_sum(cfg) -> None: return 0 =20 for _ in range(10): - rtstat =3D rtnl.getlink({"ifi-index": cfg.ifindex})['stats'] + rtstat =3D rtnl.getlink({"ifi-index": cfg.ifindex})['stats64'] if stat_cmp(rtstat, qstat) < 0: raise Exception("RTNL stats are lower, fetched later") qstat =3D get_qstat(cfg) --=20 2.25.1