From patchwork Wed Apr 2 00:59:31 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov <0x7f454c46@gmail.com> X-Patchwork-Id: 14035464 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7688F8837; Wed, 2 Apr 2025 01:00:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743555612; cv=none; b=s+s4WNOuLh9LzU5McgKUpP7A7kZJWiDICH1pB4y3rg99pUaAUhK0Gp+h8JjDpV51MzBqGULZiQtkmZSE4yHJBtJmIrUN5I95X2q5M76XgHG97Kvhf5MRuZ0D0KcDrGwCA7klKvOjjylcfzFVAXIydVTJlkl6ogi83BbUBR27i40= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743555612; c=relaxed/simple; bh=/ACN9qX6EOkrFeO0FdXlvcbraUtdbf8Oecbf6xTmBUc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=KonBvE/RstdRsAcQmJQdmORL2evKjnS3A7b7Cob7G9hxUxoIMo/4uGlTZjvabFPwN6owh6QgUrBPFQ5WLzLbZ1VqsxR+0+6wBmeygF2mRyvxTqU7gSj00aeI1vvnNrK4pCABWRC1HvT28v/yLnSeT83cXCB40/vp6baM1g/ONjI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZU8QSn5D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZU8QSn5D" Received: by smtp.kernel.org (Postfix) with ESMTPS id C44A4C4CEE4; Wed, 2 Apr 2025 01:00:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743555611; bh=/ACN9qX6EOkrFeO0FdXlvcbraUtdbf8Oecbf6xTmBUc=; h=From:Date:Subject:To:Cc:Reply-To:From; b=ZU8QSn5DbNG2E0S85Y2UCrLS1bRLLU2RSpMbDLuiDhm4MIiKn95CFWGQuzgKJJa6z r5EXDT2B5otmGCd+lGyoXkW/5X3sGLNeCR1+sfGgENESbngWN3bqejq+k54p+ZxHFZ ZUxtgv6kztuCAiZd+Mmr4geXm7kWgqC+PL0Sbfs3szxcXs0Tar/SY0AtpYmvOPBrIa 0hikOoklT5bVc9Q3QMA9Kam/tlu3SrMiHyGeGt98DvjCgjP3z/3T2x3QznGXSk2XJg 2jiGH/ZJvAAofAfjU8re5i1d7WmzTUMmD17i8uIklsbTLr0n0c7IGNImnilJS+RUOT PaPIZoBHoeh+g== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7A57C36010; Wed, 2 Apr 2025 01:00:11 +0000 (UTC) Date: Wed, 02 Apr 2025 01:59:31 +0100 Subject: [PATCH net-next] net/selftests: Add loopback link local route for self-connect Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250402-tcp-ao-selfconnect-flake-v1-1-8388d629ef3d@gmail.com> X-B4-Tracking: v=1; b=H4sIAPKL7GcC/zWMywrCQAwAf6XkbDCuL/BXxEM2Zm2wpmV3kULpv 7sKHodhZoGi2bTApVsg69uKjd5gt+lAevaHot0bQ6BwpAMFrDIhj1h0SDK6q1RMAz8VlZij0F7 ofIKWT1mTzb/1FVwrus4Vbs1ELooxs0v/Xf/d9sXmsK4fxrqPW5QAAAA= X-Change-ID: 20250402-tcp-ao-selfconnect-flake-e0aabc03c076 To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan Cc: netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com> X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1743555610; l=2603; i=0x7f454c46@gmail.com; s=20240410; h=from:subject:message-id; bh=VxuHQuF+lHn7Z66dGwiCR30NCU5Nd0bRf7ml37EyIQ0=; b=3aqwhOYRQXABmt30DhIo05TJTESR3xflbbuTR3dBAmI3yMdgAoZyxUVPrqaM+Ncc8k/aXIzyA mxoO5rvkEHQC0Jz5Odvs0oX666np6SxSESKORHPedn8ROHccfn/nftx X-Developer-Key: i=0x7f454c46@gmail.com; a=ed25519; pk=cFSWovqtkx0HrT5O9jFCEC/Cef4DY8a2FPeqP4THeZQ= X-Endpoint-Received: by B4 Relay for 0x7f454c46@gmail.com/20240410 with auth_id=152 X-Original-From: Dmitry Safonov <0x7f454c46@gmail.com> Reply-To: 0x7f454c46@gmail.com From: Dmitry Safonov <0x7f454c46@gmail.com> From: Dmitry Safonov <0x7f454c46@gmail.com> self-connect-ipv6 got slightly flaky on netdev: > # timeout set to 120 > # selftests: net/tcp_ao: self-connect_ipv6 > # 1..5 > # # 708[lib/setup.c:250] rand seed 1742872572 > # TAP version 13 > # # 708[lib/proc.c:213] Snmp6 Ip6OutNoRoutes: 0 => 1 > # not ok 1 # error 708[self-connect.c:70] failed to connect() > # ok 2 No unexpected trace events during the test run > # # Planned tests != run tests (5 != 2) > # # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:1 > ok 1 selftests: net/tcp_ao: self-connect_ipv6 I can not reproduce it on my machines, but judging by "Ip6OutNoRoutes" there is no route to the local_addr (::1). Looking at the kernel code, I see that kernel does add link-local address automatically in init_loopback(), but that is called from ipv6 notifier block. So, in turn the userspace that brought up the loopback interface may see rtnetlink ACK earlier than addrconf_notify() does it's job (at least, on a slow VM such as netdev). Probably, for ipv4 it's the same, judging by inetdev_event(). The fix is quite simple: set the link-local route straight after bringing the loopback interface. That will make it synchronous. Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> --- Sorry to send this during the merge window, it's a test stability fix. It seems that netdev build bot has hit the issue a couple of times, but seems not hitting it constantly at this moment: https://netdev.bots.linux.dev/flakes.html?br-cnt=150&tn-needle=tcp-ao I'm marking it net-next, so that build bot carries it until the merge closes. If it's not fine, I can re-send it after the merge window. --- tools/testing/selftests/net/tcp_ao/self-connect.c | 3 +++ 1 file changed, 3 insertions(+) --- base-commit: 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95 change-id: 20250402-tcp-ao-selfconnect-flake-e0aabc03c076 Best regards, diff --git a/tools/testing/selftests/net/tcp_ao/self-connect.c b/tools/testing/selftests/net/tcp_ao/self-connect.c index 73b2f2276f3f5410aaa74bede7f366f81761bd6e..2c73bea698a677f9aedd7bec28f6e7fee7845d2e 100644 --- a/tools/testing/selftests/net/tcp_ao/self-connect.c +++ b/tools/testing/selftests/net/tcp_ao/self-connect.c @@ -16,6 +16,9 @@ static void __setup_lo_intf(const char *lo_intf, if (link_set_up(lo_intf)) test_error("Failed to bring %s up", lo_intf); + + if (ip_route_add(lo_intf, TEST_FAMILY, local_addr, local_addr)) + test_error("Failed to add a local route %s", lo_intf); } static void setup_lo_intf(const char *lo_intf)