From nobody Tue Dec 16 03:22:32 2025 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (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 E6F8FF519; Mon, 11 Mar 2024 12:24:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710159895; cv=none; b=M54ya5rvgrC0CBVNAWJOBKaZ0Ceyb5FBo780RzXCTvMWUh65qzbHAjGAhiiq0RITj305Bt7f4UTM5hF35UVQLTGg7vG4xx0OWYACYtKuXIesnnb5Y2E17pjSstnYwibdYlNzeWIsTyNej1Kmnwv0swdbk+rIHCoL0rQ0yB2g0No= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710159895; c=relaxed/simple; bh=LluHyhjKemLvziSLq4mu73Bj2Ez4L1mtMOYpKAIdpW8=; h=From:To:Cc:Subject:Date:Message-Id; b=Jahq4AfxTBidA+pDAUhzGweIwQpoFAg8OOFnEBeEV+W1+emM/eCTxiYY19ixtUhzRoOo3KEehYcdhGh7uee3OzTeUTT1qGOQqk6B+mzYrTm812dr7XxIaG1DPdT0EZNnKjiOW4R9k/q7SjyMGfyZpsFpQcBxB9rvslRUuvFh1O4= 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=DUDGwidr; arc=none smtp.client-ip=209.85.214.169 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="DUDGwidr" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-1dd8ee2441dso2357485ad.1; Mon, 11 Mar 2024 05:24:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1710159893; x=1710764693; darn=vger.kernel.org; h=message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=NJV6iNofzvP9/1KByDDXNTrF5EbVufMaGdHaNE1qGbU=; b=DUDGwidrhzU+TsTaXz6zPbjio/2q/ICe6r2zTffe9JP+zw+y4wy3uBiIcOh4LeN9p2 uTgww5iH+BXkauAygiPOFyUXnSIvVDYleloifYDmtOYOyE7X4IawfQPIxHdxyjF9M3sJ r3DiV1iRnrgvfcbR6U1Rs0X/UEu6RNh87cQ4EOq1KQRcRk/fVfv9fEQQb5USqgasTCxl 3cgtS18P1bH1g1+p5dxlwvuzzwZO3pV1TcbMqrE6/AgNQjCZJh0wyjvtxRUARSEXSEAL UBqYijAkzET92quzZXugrq2rBCSycnGHGcOPpihkDLy2HvHJTP3In41dFmFMQ6DS1sDi MNuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710159893; x=1710764693; h=message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=NJV6iNofzvP9/1KByDDXNTrF5EbVufMaGdHaNE1qGbU=; b=Ub67cpu3aoBLQvBt+9ZNBx0gflUP9cwDWZMjFuf50E4e1HTaUcBrqpU1DkpIFAo5tI oCZp8d0kTh5YEjNU/yfp1L0ryuh8xJqplzQtpyUTCyo+J6vPo4a59MGPVMEeWQF0EtRz 0Ou4eGcom6u+yH8UMqnRXCFpLm+8UAHjgAeCTu+BgykcrNugoKIcU2GsmfFKMeYeekcp 1C8kgxmjnJvKJIpsnMvlTuFzpAl90m+peLQuceXuXcCZ1uciTXv2e8KMkmL38+H4w5hH TVvUNkHeAirdjqQgS9MrGikEZhOQXWv8mClqMaqt+2YIc7zwnKlI7WCB5mqliKbyaeRI V4zg== X-Forwarded-Encrypted: i=1; AJvYcCW+V86w8cUGGbOhH8OLH06fCgt372grMH14so5x7M5udG8FJniucuhLv765g+/znlZ5A+e5eC6Rxskfa+GzmMqomnYG8kjk X-Gm-Message-State: AOJu0YxIrwajbXb2oKwDD5Sdn63pCondr8NWhV+QNudAfqCeXVgJq7pE 7TcO1CCIoHTgT9hdY13C8jVuLjb4KS2S6FBjtDml5h/dn8p7Qz+tP+w9mjFHBP/1RF1c X-Google-Smtp-Source: AGHT+IHck0HQwvtlHJQzVHVrty9+g5PpjZj7C8mI81TwnrdjValzLLBDT+ZhtfYoISQ5QsL8BOBcIg== X-Received: by 2002:a05:6a20:9587:b0:1a1:67a6:511e with SMTP id iu7-20020a056a20958700b001a167a6511emr8859997pzb.2.1710159892844; Mon, 11 Mar 2024 05:24:52 -0700 (PDT) Received: from localhost.localdomain ([111.194.45.84]) by smtp.gmail.com with ESMTPSA id p48-20020a056a0026f000b006e69a142458sm1075106pfw.213.2024.03.11.05.24.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Mar 2024 05:24:52 -0700 (PDT) From: Zheng Li To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, nhorman@tuxdriver.com, davem@davemloft.net, jmorris@namei.org Cc: James.Z.Li@Dell.com Subject: [PATCH] neighbour: guarantee the localhost connections be established successfully even the ARP table is full Date: Mon, 11 Mar 2024 20:24:01 +0800 Message-Id: <20240311122401.6549-1-lizheng043@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Zheng Li Inter-process communication on localhost should be established successfully= even the ARP table is full, many processes on server machine use the localhost to communicate such as c= ommand-line interface (CLI), servers hope all CLI commands can be executed successfully even the arp tab= le is full. Right now CLI commands got timeout when the arp table is full. Set the parameter of exempt_from_gc to be true for LOOPBACK net device to keep localhost neigh in arp table, not removed by gc. the steps of reproduced: server with "gc_thresh3 =3D 1024" setting, ping server from more than 1024 = IPv4 addresses, run "ssh localhost" on console interface, then the command will get timeout. Signed-off-by: Zheng Li --- net/core/neighbour.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 552719c3bbc3..d96dee3d4af6 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -734,7 +734,10 @@ ___neigh_create(struct neigh_table *tbl, const void *p= key, struct neighbour *__neigh_create(struct neigh_table *tbl, const void *pkey, struct net_device *dev, bool want_ref) { - return ___neigh_create(tbl, pkey, dev, 0, false, want_ref); + if (dev->flags & IFF_LOOPBACK) + return ___neigh_create(tbl, pkey, dev, 0, true, want_ref); + else + return ___neigh_create(tbl, pkey, dev, 0, false, want_ref); } EXPORT_SYMBOL(__neigh_create); =20 --=20 2.17.1