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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9A4A8C43460 for ; Thu, 8 Apr 2021 06:18:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 646E261165 for ; Thu, 8 Apr 2021 06:18:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229922AbhDHGSh (ORCPT ); Thu, 8 Apr 2021 02:18:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:34492 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229691AbhDHGSf (ORCPT ); Thu, 8 Apr 2021 02:18:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 67CA5610E6; Thu, 8 Apr 2021 06:18:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617862704; bh=LLpGNyyaEfTjFDfZsFVz/KgbgvxlPflrA1HYb4wICzU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fd2VC2NULo+VYsMZDFWiBsDRCAy1NIZrdJvFzcwcBasVpVgoGsqNl5DC0vx8THQQY 2OPW3R+idDLnTgAvMx5URPv2y/iU2Gzgi6D87dCRQfohRQi76ObCr4Bza/WbKLV93F /M/yYa1hAcLugm0uENUa2/oKw7FEjHqlV8xGfnh0= Date: Thu, 8 Apr 2021 08:18:21 +0200 From: Greg KH To: Josh Poimboeuf Cc: Luis Chamberlain , Minchan Kim , keescook@chromium.org, dhowells@redhat.com, hch@infradead.org, mbenes@suse.com, ngupta@vflare.org, sergey.senozhatsky.work@gmail.com, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt , Peter Zijlstra , Jessica Yu , Thomas Gleixner , Linus Torvalds Subject: Re: [PATCH 1/2] zram: fix crashes due to use of cpu hotplug multistate Message-ID: References: <20210312183238.GW4332@42.do-not-panic.com> <20210319190924.GK4332@42.do-not-panic.com> <20210322204156.GM4332@42.do-not-panic.com> <20210401235925.GR4332@42.do-not-panic.com> <20210407201746.ueijmegmpbyq5quv@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210407201746.ueijmegmpbyq5quv@treble> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Apr 07, 2021 at 03:17:46PM -0500, Josh Poimboeuf wrote: > On Fri, Apr 02, 2021 at 09:54:12AM +0200, Greg KH wrote: > > On Thu, Apr 01, 2021 at 11:59:25PM +0000, Luis Chamberlain wrote: > > > As for the syfs deadlock possible with drivers, this fixes it in a generic way: > > > > > > commit fac43d8025727a74f80a183cc5eb74ed902a5d14 > > > Author: Luis Chamberlain > > > Date: Sat Mar 27 14:58:15 2021 +0000 > > > > > > sysfs: add optional module_owner to attribute > > > > > > This is needed as otherwise the owner of the attribute > > > or group read/store might have a shared lock used on driver removal, > > > and deadlock if we race with driver removal. > > > > > > Signed-off-by: Luis Chamberlain > > > > No, please no. Module removal is a "best effort", if the system dies > > when it happens, that's on you. I am not willing to expend extra energy > > and maintance of core things like sysfs for stuff like this that does > > not matter in any system other than a developer's box. > > So I mentioned this on IRC, and some folks were surprised to hear that > module unloading is unsupported and is just a development aid. > > Is this stance documented anywhere? > > If we really believe this to be true, we should make rmmod taint the > kernel. My throw-away comment here seems to have gotten way more attention than it deserved, sorry about that everyone. Nothing is supported for anything here, it's all "best effort" :) And I would love a taint for rmmod, but what is that going to help out with? thanks, greg k-h