From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8A57F1C84DC; Mon, 1 Jun 2026 02:04:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780279452; cv=none; b=MTuQ5uSQvL1caAmO7CuVogw+5O19l1xs9KRs7Uw7qGaelpLXZl11qKPnMbPXv+OzAKijKEoIlYE9g1aVrjfHiEkNQiiL42AsEoXrc9V5oIpz6mv7cx4OXTSlnrXmmuOfrT6avmYcVTg4X4M6WuK+jaltZ7I2ojWyu2is1xYJSwo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780279452; c=relaxed/simple; bh=h0Ztc4WJkTtsG1wcuJWedsv2JjTu3Z6o1RPULrAyi9A=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HAx0zcnvMjcuhqa+8XtBGh0uje/GKyzp5vNpK1vfx4unH53nSKrRvH6H8/L6/L+nMHx3KXAk/zyknCOu2r8xyJ/FpmK6g7dlWyvnDYXEEv5FoPRqiJOD2XFXf6SL+YfYPz6mXLHln/sbqzVUOoFx5LHZFPlObevxzyfTmtesqx0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RN4V6h6D; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RN4V6h6D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4A1C1F00893; Mon, 1 Jun 2026 02:04:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780279450; bh=ZV64leSxu1pkNR1zoe4fbmf6hVyF9H0oVvkHjx4bMbk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=RN4V6h6DCUKy0ZCqCEpUM6QGoCstN/EXlPV3IQrJ53tgwW061pvHoYymXg2Dg6iOu Lw1Dg4XvfCpoS3dwK9b82KXk4lKCvA4Jdg7hW7q+fgchOFx6Fc2xJafaKJ/PRgkaz/ k/kV/XXG8PJNvNUKvh8xRvnA1Yzmlvb5TF/sB6WrHuR97VBxTF8+sVfSrDy1SoZjFm aldbkd7Bxlz3QUtbjXPwcc4O1nW1rnacEsHSoe5Ue1WTjKh/CJkNNs1P+ZfupBFkzv RzCtgDuY//YUUcXgkS5uNhb2jKNi/x93neSDaHDxyP04xJQy/3zWVIL/KVP/9iKzjr 2v6y4wOUPV7YA== Message-ID: <5079261a-79e5-421b-bf6a-a511acaaeca4@kernel.org> Date: Mon, 1 Jun 2026 12:03:59 +1000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net v2] Revert "ipv6: preserve insertion order for same-scope addresses" Content-Language: fr To: Stefano Brivio , Fernando Fernandez Mancera Cc: netdev@vger.kernel.org, yuhuang@redhat.com, justin.iurman@gmail.com, horms@kernel.org, pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, davem@davemloft.net, idosch@nvidia.com, dsahern@kernel.org, Chris Adams , David Gibson , Beniamino Galvani , Thorsten Leemhuis , Andrew Lunn , ihuguet@redhat.com, regressions@lists.linux.dev References: <20260529112357.5079-1-fmancera@suse.de> <20260529134045.56330243@elisabeth> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Stefano, On 29/05/2026 21:41, Stefano Brivio wrote: > On Fri, 29 May 2026 13:23:57 +0200 > Fernando Fernandez Mancera wrote: > >> Chris Adams reported that preserving insertion order for same-scope >> addresses is causing SSH connections to be dropped after stopping a VM >> while running NetworkManager. >> >> NetworkManager caches the IPv6 address configuration, when a RA arrives, >> it determines the list of addresses to configure and checks if the >> addresses are already in the right order in the kernel. If they aren't, >> NetworkManager removes and re-adds them to achieve the desired order. >> >> As the order changes, NetworkManager is confused and reconfigures the >> addresses on every update. In addition, this would also affect to cloud >> tooling that relies on IPv6 addresses order to identify primary and >> secondaries addresses. > > By the way, I'm still looking into this part, trying to find > "problematic" examples. > > And I couldn't find any, yet, because it looks like there's always a > _single_ IPv6 address being used as a secondary for a primary IPv4 > address. FYI, the order change also affected some specific scripts, e.g. here with MPTCP and packetdrill: https://github.com/multipath-tcp/packetdrill/commit/1b7cd4482ce8 Because the order was not "natural" before, and different from IPv4, a workaround was needed to keep the same order. I was happy to remove it, but now it looks like I need to re-apply it :) It would be nice to get the "natural" order back without breaking the userspace (or with a way to choose the order). Cheers, Matt -- Sponsored by the NGI0 Core fund.