From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f177.google.com (mail-yw1-f177.google.com [209.85.128.177]) (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 9569F2DB789 for ; Sat, 4 Apr 2026 15:08:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775315299; cv=none; b=cbbRWr5//7RV8dRMRPIARW9pMpBm8nfuXD/N5FHYQvwjw9FcGzckIWiCuSsK4PM+1fmdUWLkHM5VEeADbgRGDnFcGclyu9nQwwhSxR9/UTRJwJk74RVYyyva1RN1f0o8NB8Sy2DbCmeERVes64BUFRY3C0JMGlxJg04xtQgXUo4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775315299; c=relaxed/simple; bh=GKnP9FkbLRMPwQb91TBQRJYV4zaTPwKQgjogh0/oxyE=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=YqjbNfMEowLW59JdxOllg1cpK23u0IHeaFd3kY49PvrmTm117c1/yE2UO9+uP/HQQzApGjw6yUUVOxQ5AhCWFKPLtQZiefOX8ktDNgB9b5ihnuru1s3vIREOihDV+Ve2NevMdRAEwfq8XkMKs5ev0Lnz61uCtVVaCc/x5rvEpZg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=n9GTJQex; arc=none smtp.client-ip=209.85.128.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="n9GTJQex" Received: by mail-yw1-f177.google.com with SMTP id 00721157ae682-793fdbb8d3aso27202627b3.3 for ; Sat, 04 Apr 2026 08:08:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775315296; x=1775920096; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=bpIgdEywYJarOeXBnQPDMHU5G9TMjrWQTBzqgz6cG/I=; b=n9GTJQexpgcf6U20q93ODJoV/U8OntFHnfTdXhd1xVFUQcJ3T0oFQEKjqmcMbdMf54 sC/mXu6YDXGnABcsUK0Qt4Kv+6OuntKSBb2dqalQ/HwNET7Dh5rI2HVYQFccVskAGlPp LQm4d13JZElqZX4kfeqU2Fi1l1007PYgYjyenFRtrn0zWasuhUjoy3LfJW096dY7pf+5 0YHMiPdjuvwInu4BrdUru5hFFHV3VOmciaYGfqTFBFgQ9EtqpdikjBha7wuVcQXKz4cM UDe4Cjh8q3XqCbIMQRXohXFUmP74Wr7vhn4GGPvsz934XbTwh2m/gTkuXt6YKLuZ5nbY CaQA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775315296; x=1775920096; h=content-transfer-encoding:mime-version:subject:references :in-reply-to:message-id:cc:to:from:date:x-gm-gg:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=bpIgdEywYJarOeXBnQPDMHU5G9TMjrWQTBzqgz6cG/I=; b=kE9UJXv8UoCq0ePCYrmImQIYgCqeOanT6EzmXXrxQj3NUwNtZ/JJq3EVkCT4YGhLs9 SHSDhK9VaOoKPYI7ZiuWSwt3ULuvsi5pmG3USTr/JvlhrqxO1wh+6ruuAVGVOWcuyfgk 3sjzBJGBiFkfruyQqEl8X8hDB+Ie09QwvwsxFM4ZNFEPV9iPMRnM6mNWEBCcONMsJHgu jTjwSSc7oLz9K3GeDDoEwvXohvUPHqJw218jsMwO1EEHd4aHtkujpiqj8NCdiYvsrCBs Fc2Nuo3K14E1C/zdKAjI240l+oixY6/fuF1iuhqxsQk9z2mtGYOnH99EYVDA6sCrHqZ1 6aDQ== X-Forwarded-Encrypted: i=1; AJvYcCXzjVXIIyr3idTIWjgmr35nGmLLo8NMr4X9aTJFj1WAQ+zBvv/WGejEwiIdz5aJGnQeyQturr4kcyQPTro=@vger.kernel.org X-Gm-Message-State: AOJu0Ywyz3t1zSYn1J3kZ0/p+98NgTZUB1oNXTddbwNKF9qP3IQOXcfX XkfyPuO30eDgLAxSAX3Eu6zqISmmgZuFSjl6FiORCP0ry6FyiI3FBS89 X-Gm-Gg: AeBDietlYCmI0jPXrqJtHLPW52R/j9P4Rks1mj44q+0zq0/oNmBv7l0Bq1dlzWn+RQb KMzALaz8vvWfdAn2bFjl6zDpN7RMYbS2GFl6iUogaY9YvI+ekIhRSLHtA/D7gks6IRFKYKk+YkA TY9TKWRO97PWHZALYyuHHp7des5MMRYkBYiFBUuiT+gViQrdvqh+2uTYDQyDN79shTs+IZb4YyC AJpOvXHLWyLIfgw9LauG300a4kM3WCZuzxwgkCbH5vg4V/CNsVTiGKQLkW+q4r+ZPksTF1M4GUq QNAJmcKWAEFpv7PrlplabbEviIjz+QdKbQwR7NDEiGqCZh1mAJUTA5OevGbT9W+c0O7Dv2tnMmS JfX82u4ne8RKJuh5zAsESqhEg0w2+pxDYOVg8ypTgqnjydhHL2kBOowmEOEq9BSnfa5KI7iIQf5 qYlqlFWhzzl3996zaq7UBSqrimShSKENqVAvXOTzBKgtX4cxsU7UVTvluoqodghVaj8aqjfFoti +c+ X-Received: by 2002:a05:690c:110:b0:7a4:80ce:825e with SMTP id 00721157ae682-7a4d41b66d1mr68237397b3.25.1775315296259; Sat, 04 Apr 2026 08:08:16 -0700 (PDT) Received: from gmail.com (172.165.85.34.bc.googleusercontent.com. [34.85.165.172]) by smtp.gmail.com with ESMTPSA id 00721157ae682-7a36e228f75sm32114967b3.10.2026.04.04.08.08.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 04 Apr 2026 08:08:15 -0700 (PDT) Date: Sat, 04 Apr 2026 11:08:15 -0400 From: Willem de Bruijn To: Joe Damato , netdev@vger.kernel.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan Cc: andrew+netdev@lunn.ch, linux-kernel@vger.kernel.org, willemb@google.com, Joe Damato , linux-kselftest@vger.kernel.org Message-ID: In-Reply-To: <20260403233240.178948-3-joe@dama.to> References: <20260403233240.178948-1-joe@dama.to> <20260403233240.178948-3-joe@dama.to> Subject: Re: [net-next v2 2/3] selftests/net: Test PACKET_STATISTICS drops Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Joe Damato wrote: > Extend psock_snd to test drops by setting a tiny receive buffer and > sending a large burst of packets. > > Signed-off-by: Joe Damato > --- > tools/testing/selftests/net/psock_snd.c | 48 ++++++++++++++++++++---- > tools/testing/selftests/net/psock_snd.sh | 5 +++ > 2 files changed, 46 insertions(+), 7 deletions(-) > > v2: > - Remove do_tx argument and use global cfg_drop instead > > diff --git a/tools/testing/selftests/net/psock_snd.c b/tools/testing/selftests/net/psock_snd.c > index 5be481a3d2bd..81096df5cffc 100644 > --- a/tools/testing/selftests/net/psock_snd.c > +++ b/tools/testing/selftests/net/psock_snd.c > @@ -39,6 +39,7 @@ static bool cfg_use_gso; > static bool cfg_use_qdisc_bypass; > static bool cfg_use_vlan; > static bool cfg_use_vnet; > +static bool cfg_drop; > > static char *cfg_ifname = "lo"; > static int cfg_mtu = 1500; > @@ -49,6 +50,8 @@ static uint16_t cfg_port = 8000; > /* test sending up to max mtu + 1 */ > #define TEST_SZ (sizeof(struct virtio_net_hdr) + ETH_HLEN + ETH_MAX_MTU + 1) > > +#define BURST_CNT (1000) > + > static char tbuf[TEST_SZ], rbuf[TEST_SZ]; > > static unsigned long add_csum_hword(const uint16_t *start, int num_u16) > @@ -212,13 +215,14 @@ static void do_send(int fd, char *buf, int len) > if (ret != len) > error(1, 0, "write: %u %u", ret, len); > > - fprintf(stderr, "tx: %u\n", ret); > + if (!cfg_drop) > + fprintf(stderr, "tx: %u\n", ret); > } > > static int do_tx(void) > { > const int one = 1; > - int fd, len; > + int i, fd, len; > > fd = socket(PF_PACKET, cfg_use_dgram ? SOCK_DGRAM : SOCK_RAW, 0); > if (fd == -1) > @@ -242,6 +246,10 @@ static int do_tx(void) > > do_send(fd, tbuf, len); > > + if (cfg_drop) > + for (i = 0; i < BURST_CNT; i++) > + do_send(fd, tbuf, len); > + > if (close(fd)) > error(1, errno, "close t"); > > @@ -290,6 +298,7 @@ static void do_rx(int fd, int expected_len, char *expected) > static int setup_sniffer(void) > { > struct timeval tv = { .tv_usec = 100 * 1000 }; > + const int one = 1; > int fd; > > fd = socket(PF_PACKET, SOCK_RAW, 0); > @@ -299,6 +308,10 @@ static int setup_sniffer(void) > if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv))) > error(1, errno, "setsockopt rcv timeout"); > > + if (cfg_drop) > + if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &one, sizeof(one))) > + error(1, errno, "setsockopt SO_RCVBUF"); > + > pair_udp_setfilter(fd); > do_bind(fd); > > @@ -309,7 +322,7 @@ static void parse_opts(int argc, char **argv) > { > int c; > > - while ((c = getopt(argc, argv, "bcCdgl:qt:vV")) != -1) { > + while ((c = getopt(argc, argv, "bcCdDgl:qt:vV")) != -1) { > switch (c) { > case 'b': > cfg_use_bind = true; > @@ -323,6 +336,9 @@ static void parse_opts(int argc, char **argv) > case 'd': > cfg_use_dgram = true; > break; > + case 'D': > + cfg_drop = true; > + break; > case 'g': > cfg_use_gso = true; > break; > @@ -367,11 +383,23 @@ static void check_packet_stats(int fd) > if (getsockopt(fd, SOL_PACKET, PACKET_STATISTICS, &st, &len)) > error(1, errno, "getsockopt packet statistics"); > > - if (st.tp_packets != 1) > - error(1, 0, "stats: tp_packets %u != 1", st.tp_packets); > + if (cfg_drop) { > + /* PACKET_STATISTICS reports all packets seen (including > + * drops) in tp_packets > + */ > + if (st.tp_packets < st.tp_drops) > + error(1, 0, "stats: tp_packets %u < tp_drops %u", > + st.tp_packets, st.tp_drops); > > - if (st.tp_drops != 0) > - error(1, 0, "stats: tp_drops %u != 0", st.tp_drops); > + if (st.tp_drops == 0) > + error(1, 0, "stats: expected drops but tp_drops == 0"); > + } else { > + if (st.tp_packets != 1) > + error(1, 0, "stats: tp_packets %u != 1", st.tp_packets); > + > + if (st.tp_drops != 0) > + error(1, 0, "stats: tp_drops %u != 0", st.tp_drops); > + } > > /* verify clear on read */ > memset(&st, 0xff, sizeof(st)); > @@ -396,6 +424,11 @@ static void run_test(void) > > total_len = do_tx(); > > + if (cfg_drop) { > + check_packet_stats(fds); > + goto out; > + } Sashiko pointed out that there may be a race here between rx processing in the softirq and check_packet_stats. Seems plausible. > /* BPF filter accepts only this length, vlan changes MAC */ > if (cfg_payload_len == DATA_LEN && !cfg_use_vlan) { > do_rx(fds, total_len - sizeof(struct virtio_net_hdr), > @@ -405,6 +438,7 @@ static void run_test(void) > > do_rx(fdr, cfg_payload_len, tbuf + total_len - cfg_payload_len); > > +out: > if (close(fds)) > error(1, errno, "close s"); > if (close(fdr)) > diff --git a/tools/testing/selftests/net/psock_snd.sh b/tools/testing/selftests/net/psock_snd.sh > index 1cbfeb5052ec..b6ef12fad5d5 100755 > --- a/tools/testing/selftests/net/psock_snd.sh > +++ b/tools/testing/selftests/net/psock_snd.sh > @@ -92,4 +92,9 @@ echo "raw gso max size" > echo "raw gso max size + 1 (expected to fail)" > (! ./in_netns.sh ./psock_snd -v -c -g -l "${max_mss_exceeds}") > > +# test drops statistics > + > +echo "test drops statistics" > +./in_netns.sh ./psock_snd -D > + > echo "OK. All tests passed" > -- > 2.52.0 >