From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC033C433FE for ; Wed, 2 Nov 2022 03:40:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230118AbiKBDkL (ORCPT ); Tue, 1 Nov 2022 23:40:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229785AbiKBDkK (ORCPT ); Tue, 1 Nov 2022 23:40:10 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 557CF26AC1; Tue, 1 Nov 2022 20:40:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D74796172F; Wed, 2 Nov 2022 03:40:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF521C433D7; Wed, 2 Nov 2022 03:40:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1667360408; bh=YvIE6halxY+/sZPI1kuhiNcmZGBmKfv091gJ/Usx2HU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=dECRwqqCEG/Ct8DxQAtr8C782XsNfmXDEDV81c7jZKYHL8WkVDivFge03dx1WFqYt 3hddwowmUhVE6gknEMzNvvrV/wsz7JrN/ozMeEGjaaXPWIOWIRxp/9h1MoLIOiQwMK m0UZXjj7iZf3lHXapvRo4IscVwD5GGkerF9tXaUcG2hsHqrP6COh96FjjIeZ4htbmF mFB4YySnu96McpPBejZ3mdmdv/jEG+W6tPmK+BTEau0MTtdnms9iVycaeqUqzdkPd/ o6R0GM1r1Aiww/bDz31IF28c5O+5WQA6FehCguOjobRPpTDlLwwpKqIIcU0ZqSxyhr 9dYRFoLcyoG/A== Date: Tue, 1 Nov 2022 20:40:06 -0700 From: Jakub Kicinski To: Andrew Lunn Cc: Andy Ren , netdev@vger.kernel.org, richardbgobert@gmail.com, davem@davemloft.net, wsa+renesas@sang-engineering.com, edumazet@google.com, petrm@nvidia.com, pabeni@redhat.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, roman.gushchin@linux.dev Subject: Re: [PATCH net-next v2] netconsole: Enable live renaming for network interfaces used by netconsole Message-ID: <20221101204006.75b46660@kernel.org> In-Reply-To: References: <20221102002420.2613004-1-andy.ren@getcruise.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 2 Nov 2022 01:48:09 +0100 Andrew Lunn wrote: > Changing the interface name while running is probably not an > issue. There are a few drivers which report the name to the firmware, > presumably for logging, and phoning home, but it should not otherwise > affect the hardware. Agreed. BTW I wonder if we really want to introduce a netconsole specific uAPI for this or go ahead with something more general. A sysctl for global "allow UP rename"? We added the live renaming for failover a while back and there were no reports of user space breaking as far as I know. So perhaps nobody actually cares and we should allow renaming all interfaces while UP? For backwards compat we can add a sysctl as mentioned or a rtnetlink "I know what I'm doing" flag? Maybe print an info message into the logs for a few releases to aid debug? IOW either there is a reason we don't allow rename while up, and netconsole being bound to an interface is immaterial. Or there is no reason and we should allow all.