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=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 9BBF4CA9EC7 for ; Sat, 2 Nov 2019 14:03:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E76F2080F for ; Sat, 2 Nov 2019 14:03:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="m6LW3TEs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbfKBOD6 (ORCPT ); Sat, 2 Nov 2019 10:03:58 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:33221 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726454AbfKBOD6 (ORCPT ); Sat, 2 Nov 2019 10:03:58 -0400 Received: by mail-pf1-f193.google.com with SMTP id c184so8947586pfb.0 for ; Sat, 02 Nov 2019 07:03:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=cIqRCDelQ2QzV3ADiNrggvNsE7uK4SPsRu91QQliWOM=; b=m6LW3TEsSigobj/S/Uuy6wHLViVXGdoGFXMWyLaGj0NH+ujv0Ybt+rbgh51DMpHi6y lD1z1FRy7fXhTLx7dN225D0z0pUV3tdr9z36Yqfu/81U2zEhFRDzYWhapjzrp5TnZgm0 7azXh9RhlCHlD4Q5VrNNB0cCiSrFYeKInvIdyIlze5/1RTWbavObzMnbLFj2lE8EmdQh Hr20d3llTHHbAttzTasScpYQTxOLVKVtI3A0Hb6R+yHhpQGQ4a3vGXj3lio0qV6E8wMB BXjgV/cPuKDjBC86VFPV1nYyoHprUEmWAlssZOr9FWNkzGH0IjL80Zw8Efn5vX/Qh++y npFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=cIqRCDelQ2QzV3ADiNrggvNsE7uK4SPsRu91QQliWOM=; b=o4RUNClfXRPS1N4GNBvSPw6Zlj7kXA0g4rHs98zRr8TX/UxszcCLunprFE4ULSCqXy 8+RGK47SK4Rp7LWXPmJY2lSQUxpCO4u+wDZHEnbDn2NJdejEqvM7zEiiHJsY6RgLJZU7 8NaztM9VZA7hR0el7zD+dITc6SvP0ogMp9q/SpAq4QRQhAWHo4bS+2AHIGRzMVlQ0ZR1 6VlXGJdF/qIywrYVOrq/OMiMTDgKyd0B91sgdhk/rXL5e0UfhoO1fcLLm46ORk56UN5a qM6XFtSEL6dxFEN+pc6SMMGRIiS0z8j0nHH/XtBbCjvHOW0H84Ko5N6jVYD/O5Pr3oIu xd4w== X-Gm-Message-State: APjAAAWzfi4Um5U1Wsjl43a30Xc6xZYUxHtSLxHKacwkzr2Wupxpnt+U uMG4XGfbQ48BptkvaqVySsJVUA== X-Google-Smtp-Source: APXvYqxFCfGRNK8kJt+Um+HkJ7nPNPJhWf7yglDrAdKMcBLPmJavyuWIE7Ywg6m99GLm5NcuYv83Cg== X-Received: by 2002:a62:e214:: with SMTP id a20mr4798191pfi.193.1572703436397; Sat, 02 Nov 2019 07:03:56 -0700 (PDT) Received: from [192.168.1.188] ([66.219.217.79]) by smtp.gmail.com with ESMTPSA id 18sm10302057pfp.100.2019.11.02.07.03.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 02 Nov 2019 07:03:55 -0700 (PDT) Subject: Re: [PATCH] blk-mq: avoid sysfs buffer overflow by too many CPU cores To: Ming Lei Cc: linux-block@vger.kernel.org, stable@vger.kernel.org References: <20191102080215.20223-1-ming.lei@redhat.com> From: Jens Axboe Message-ID: Date: Sat, 2 Nov 2019 08:03:54 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191102080215.20223-1-ming.lei@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 11/2/19 2:02 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 of > hctx via /sys/block/$DEV/mq/$N/cpu_list. > > So use snprintf for avoiding the potential buffer overflow. > > This version doesn't change the attribute format, and simply stop > to show CPU number if the buffer is to be overflow. Applied, thanks. -- Jens Axboe