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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCDD4C43217 for ; Tue, 19 Oct 2021 19:38:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B57F60D42 for ; Tue, 19 Oct 2021 19:38:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234626AbhJSTlJ (ORCPT ); Tue, 19 Oct 2021 15:41:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230432AbhJSTlH (ORCPT ); Tue, 19 Oct 2021 15:41:07 -0400 Received: from bombadil.infradead.org (unknown [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 980F3C06161C; Tue, 19 Oct 2021 12:38:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=zY/TOEsZiQ3A5NcBB8ThTVV+O2F16AgeBhmjTIEWu7w=; b=ZStJ/DXqq1wAvyAXrcCXgyZYTL AbzgYczpU5nQMNid+f6J4ibhGfIyJqjlykgL/v5dQDL+HLL2ZsC8YzEuzI0LfocO782ZVzleec++r nemnPop2nMpQedimhX/v2i4cCuXgnPpeK6heH5Ap9yMKk4nh3OaeiJGvI3eUU4XHcMl0vjslhWOe5 P9NcT7KFmWZwL11f5OGcZoJ2cX/dR6taK+9lafK+TBHdeohoKfUbhikMaztwxtLSQuiYMrZo2FQTt plVx+iPPZEbaRCRqP6vOSOGjS8ns1X3V2Eebf/S6yYCzwJrYDx99KaEN9zNPeJnEs5Db9Uct4ni5B qMqkvecA==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcuwc-002XBh-TJ; Tue, 19 Oct 2021 19:38:43 +0000 Date: Tue, 19 Oct 2021 12:38:42 -0700 From: Luis Chamberlain To: Ming Lei Cc: Benjamin Herrenschmidt , Paul Mackerras , tj@kernel.org, gregkh@linuxfoundation.org, akpm@linux-foundation.org, minchan@kernel.org, jeyu@kernel.org, shuah@kernel.org, bvanassche@acm.org, dan.j.williams@intel.com, joe@perches.com, tglx@linutronix.de, keescook@chromium.org, rostedt@goodmis.org, linux-spdx@vger.kernel.org, linux-doc@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 11/12] zram: fix crashes with cpu hotplug multistate Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 20, 2021 at 12:39:22AM +0800, Ming Lei wrote: > On Tue, Oct 19, 2021 at 08:50:24AM -0700, Luis Chamberlain wrote: > > So do you want to take the position: > > > > Hey driver authors: you cannot use any shared lock on module removal and > > on sysfs ops? > > IMO, yes, in your patch of 'zram: fix crashes with cpu hotplug multistate', > when you added mutex_lock(zram_index_mutex) to disksize_store() and > other attribute show() or store() method. You have added new deadlock > between hot_remove_store() and disksize_store() & others, which can't be > addressed by your approach of holding module refcnt. > > So far not see ltp tests covers hot add/remove interface yet. Care to show what commands to use to cause this deadlock with my patches? Luis