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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86E2AC433E0 for ; Fri, 19 Feb 2021 16:52:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4564C64E57 for ; Fri, 19 Feb 2021 16:52:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230015AbhBSQwT (ORCPT ); Fri, 19 Feb 2021 11:52:19 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:43163 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229577AbhBSQwR (ORCPT ); Fri, 19 Feb 2021 11:52:17 -0500 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 11JGog0G026060 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 19 Feb 2021 11:50:42 -0500 Received: by cwcc.thunk.org (Postfix, from userid 15806) id E836615C342A; Fri, 19 Feb 2021 11:50:41 -0500 (EST) Date: Fri, 19 Feb 2021 11:50:41 -0500 From: "Theodore Ts'o" To: Greg Kroah-Hartman Cc: Jari Ruusu , Willy Tarreau , Jari Ruusu , Scott Branden , Linux ARM , LKML , BCM Kernel Feedback Subject: Re: 5.10 LTS Kernel: 2 or 6 years? Message-ID: References: <602E766F.758C74D8@users.sourceforge.net> <20210218143341.GB13671@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 19, 2021 at 12:16:12PM +0100, Greg Kroah-Hartman wrote: > > Great! Can you run 'git bisect' on the 4.14.y stable tree to find the > offending change? To be fair, especially with WiFi bugs, you may need to run for hours or days before you are absolutely sure that a particular bisection point will result in the the locking/kernel crash bug to manifest itself. Worse, you have to be actively using the Wifi in order to see the problem, and in some cases, it only triggers when you switch between AP's, so you have to be actively using it in the work office, and taking it between conference rooms, only to see your machine crash taking your unsaved work, email drafts, etc. with it. That being said, users should at least report the bug. (That's what I did, when I ran into this a bunch of years ago, with an explanation of "I'm trying to do a bisect, but it may take a few weeks for me to figure out what the !@#!? is going on. In my case, I was trying to use upstream -rcX kernels to dogfood on my work laptop, but the principle is the same.) Ultiumately, I solved the problem, by switching laptops to one that didn't use an NVidia GPU (which sometimes forced me to stay 1-2 upstream versions behind, making life even more difficult when debugging these issues, until the out-of-tree video driver got updated to work with newer upstream), and which also had WiFi hardware which was less subject to these issues. It's unfortunate, but not all hardware is as well supported on Linux. And in my case, because $WORK was using Enterprise WiFi systems with AP's that don't get as much testing by developers, very few other people could repro the bugs. That's life, and sometimes the only solution is to switch hardware. And/or you just use a Chromebook in those sorts of situations, separating your work/enterprise and upstream development hardware, and be done with it. :-) Cheers, - Ted 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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 540ADC433E0 for ; Fri, 19 Feb 2021 16:52:50 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8F77A64E57 for ; Fri, 19 Feb 2021 16:52:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F77A64E57 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=47/94Z3a8BK+K23mmgRBH2mC9zPtc8VmuBfQFMDLblk=; b=LiPCon+B/B6/wOatIS1Djw1ZB 65OLCVgnp33RYWw3YrTzUhXNpx3/wMjyA/W6oDkd6beon8LhGzvJUIm6YEytJErDEvZDA+/MtKA2I Glm3WciWuvwXQ9L09b5o28poJPP0mOnooBy9qJQxAjkHLJooyVqdMmPFywWkhPAJFEuVVCmq8TnLW RkXF8Q13pq5aEzVVE6pMmeHdIC3PzrvoszOavg9WZMJQS0DzC/Rba8YbdHzmkPtLOe6Pwyb+Q8zf/ /sSiSl8yQa/4teTmFcbegH6M0aN0M/1WPV6zmBoeUtNkpnC1PYlf9kFAB9Geer5RC3tvplgQLpyvX 9jR2YNPzA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lD8zn-0007PW-4v; Fri, 19 Feb 2021 16:51:11 +0000 Received: from outgoing-auth-1.mit.edu ([18.9.28.11] helo=outgoing.mit.edu) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lD8zl-0007P5-Fv for linux-arm-kernel@lists.infradead.org; Fri, 19 Feb 2021 16:51:10 +0000 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 11JGog0G026060 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 19 Feb 2021 11:50:42 -0500 Received: by cwcc.thunk.org (Postfix, from userid 15806) id E836615C342A; Fri, 19 Feb 2021 11:50:41 -0500 (EST) Date: Fri, 19 Feb 2021 11:50:41 -0500 From: "Theodore Ts'o" To: Greg Kroah-Hartman Subject: Re: 5.10 LTS Kernel: 2 or 6 years? Message-ID: References: <602E766F.758C74D8@users.sourceforge.net> <20210218143341.GB13671@1wt.eu> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210219_115109_666823_2149F9E1 X-CRM114-Status: GOOD ( 15.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jari Ruusu , Scott Branden , Jari Ruusu , LKML , BCM Kernel Feedback , Willy Tarreau , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Feb 19, 2021 at 12:16:12PM +0100, Greg Kroah-Hartman wrote: > > Great! Can you run 'git bisect' on the 4.14.y stable tree to find the > offending change? To be fair, especially with WiFi bugs, you may need to run for hours or days before you are absolutely sure that a particular bisection point will result in the the locking/kernel crash bug to manifest itself. Worse, you have to be actively using the Wifi in order to see the problem, and in some cases, it only triggers when you switch between AP's, so you have to be actively using it in the work office, and taking it between conference rooms, only to see your machine crash taking your unsaved work, email drafts, etc. with it. That being said, users should at least report the bug. (That's what I did, when I ran into this a bunch of years ago, with an explanation of "I'm trying to do a bisect, but it may take a few weeks for me to figure out what the !@#!? is going on. In my case, I was trying to use upstream -rcX kernels to dogfood on my work laptop, but the principle is the same.) Ultiumately, I solved the problem, by switching laptops to one that didn't use an NVidia GPU (which sometimes forced me to stay 1-2 upstream versions behind, making life even more difficult when debugging these issues, until the out-of-tree video driver got updated to work with newer upstream), and which also had WiFi hardware which was less subject to these issues. It's unfortunate, but not all hardware is as well supported on Linux. And in my case, because $WORK was using Enterprise WiFi systems with AP's that don't get as much testing by developers, very few other people could repro the bugs. That's life, and sometimes the only solution is to switch hardware. And/or you just use a Chromebook in those sorts of situations, separating your work/enterprise and upstream development hardware, and be done with it. :-) Cheers, - Ted _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel