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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 0D367C3A59E for ; Fri, 16 Aug 2019 14:54:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D01ED2173E for ; Fri, 16 Aug 2019 14:54:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565967279; bh=Ft48zl3UpgHiHHJcgyXOdAOG45h3Jwm4M7OBOVDUzQY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=hRqnf7JLQzzBcN+iaHP+Wqx+jBx6wTZcVoWMsZAlB2ug/yY7snyU+Cda4JYhOFzb6 tEP8yCjEGlhELQTS407RPHQ+jVamqPjBf9UTNmDpGVwzNQ1gQmwnb0OxyJFMQN6igu JTYhU4nDQKfba0SnCLvenph48gKgQMb3A4XQTFjw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727245AbfHPOyj (ORCPT ); Fri, 16 Aug 2019 10:54:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:56528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726032AbfHPOyj (ORCPT ); Fri, 16 Aug 2019 10:54:39 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BDE532086C; Fri, 16 Aug 2019 14:54:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565967278; bh=Ft48zl3UpgHiHHJcgyXOdAOG45h3Jwm4M7OBOVDUzQY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2dQJ3Sm+ddSE20a5TNWpsq5Dy11EyiF+Y95TKifH6l2vX10/2hi0GEz3IldbHHp9n tiDiDIo+3IDpP6giLbSGKXgFnC83gMf9ATaW6zUdPEx8w2q9aAB++5fPQlf937M7Kq ge60xI0hDN1CAjnCNq3AgSKDVkj2jggDJ3zkFs7c= Date: Fri, 16 Aug 2019 16:54:35 +0200 From: Greg KH To: Jens Axboe Cc: Ming Lei , linux-block@vger.kernel.org, stable@vger.kernel.org, Mark Ray Subject: Re: [PATCH] blk-mq: remove blk_mq_hw_sysfs_cpus Message-ID: <20190816145435.GA3424@kroah.com> References: <20190816074849.7197-1-ming.lei@redhat.com> <5baa0c28-6e12-5a61-0254-de0e49cf1596@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5baa0c28-6e12-5a61-0254-de0e49cf1596@kernel.dk> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Aug 16, 2019 at 08:20:42AM -0600, Jens Axboe wrote: > On 8/16/19 1:48 AM, Ming Lei wrote: > > It is reported that sysfs buffer overflow can be triggered in case > > of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in > > blk_mq_hw_sysfs_cpus_show(). > > > > This info isn't useful, given users may retrieve the CPU list > > from sw queue entries under same kobject dir, so far not see > > any active users. > > > > So remove the entry as suggested by Greg. > > I think that's a bit frivolous, there could very well be scripts or > apps that use it. Let's just fix the overflow. As no one really knows what the format is (and the patch to fix the overflow changes the format of the file), I would say that it needs to just be dropped as it is not an example of what you should be doing in sysfs. thanks, greg k-h