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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 181CCC33CB2 for ; Fri, 31 Jan 2020 07:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD1C920705 for ; Fri, 31 Jan 2020 07:02:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="gcVYhGHF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728105AbgAaHCm (ORCPT ); Fri, 31 Jan 2020 02:02:42 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:45462 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbgAaHCm (ORCPT ); Fri, 31 Jan 2020 02:02:42 -0500 Received: by mail-pf1-f195.google.com with SMTP id 2so2820596pfg.12 for ; Thu, 30 Jan 2020 23:02:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=wOI7hqK3fz5FOatl+JgLstEmzwY5hPCxPwdC6f4htY0=; b=gcVYhGHFtpUbCqyKbhsgy051T79MxaD0OdnjtYqfqze1AvFsz1IsXJQLrWD0Gg4KOX J2DsQGRsQ6WoO3xOmJp2umB2AWLPJ5FR5KkAsAeBptRvLpxCvhvY9RKPjJCI8zskqw00 ZunZhSWNWIi9qFAqnip93r1/chopEhiogdWsuG1pCjMYTfbPF4irJTdGs1hC+qQpwGOl MWXzaWUcWmY/mJp4G/UUx/oGmcY0HMQI7ereUN7p4PQ7V15zj2M6k2/bhck2sfgBkC7S d7c2puw/9abml2Z4h87xT3hYJsSYYJa0hUBwmiHfDHwRQs4uUhg0ZT2WqI0XM2p8AqlP nV0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=wOI7hqK3fz5FOatl+JgLstEmzwY5hPCxPwdC6f4htY0=; b=RHxJQo7I71q3iaxP52LkjJzMj9M8uJk+5adwWEioHAysHGJTDR9aV4njM3oXcLnE7w ZR9WUVIDbaqN7Lc+DcizgU38lympvqL+HLmCtEHsr5z8bDTi9NEh6/3TQKN4eauc5nDo g/qxuJ5v8C90EsDWpePmTwo6S8McHIcp+tJ/0QhRFd3VBgZNl1pDxvCguCloASN5pRZl VfsZ0Lhs6CycSg8x+z2WiJxgbOamCRm4gA5N3ruSexEYXwpk9+I3VlrwEVKn6r3pxkqW OHrzrToKwxoPEu+VRbdLReKZVLJEI9c4DOstRvymG5FSjYgIQxoKpiI9zfJPzHgc5VI+ ZChw== X-Gm-Message-State: APjAAAWahD37lwlMg0IzoZuhbFdj+xj6mjR7kZVGKKyQrKljyVEISSR5 6/Jg2wGvFcTUDymv0bQH4vE= X-Google-Smtp-Source: APXvYqzrf9HXTuJ47vRwuDdXyk6Q7rha2caXtba6GCDo4v9fEuaTCO33fzUk4AwnphPzGbYBjgI/jw== X-Received: by 2002:a63:28a:: with SMTP id 132mr8654803pgc.165.1580454161600; Thu, 30 Jan 2020 23:02:41 -0800 (PST) Received: from localhost ([2401:fa00:8f:203:5bbb:c872:f2b1:f53b]) by smtp.gmail.com with ESMTPSA id gc1sm8305293pjb.20.2020.01.30.23.02.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jan 2020 23:02:40 -0800 (PST) Date: Fri, 31 Jan 2020 16:02:37 +0900 From: Sergey Senozhatsky To: Nathan Chancellor Cc: Petr Mladek , Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH] printk: Convert a use of sprintf to snprintf in console_unlock Message-ID: <20200131070237.GB240941@google.com> References: <20200130221644.2273-1-natechancellor@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200130221644.2273-1-natechancellor@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (20/01/30 15:16), Nathan Chancellor wrote: > When CONFIG_PRINTK is disabled (e.g. when building allnoconfig), clang > warns: > > ../kernel/printk/printk.c:2416:10: warning: 'sprintf' will always > overflow; destination buffer has size 0, but format string expands to at > least 33 [-Wfortify-source] > len = sprintf(text, > ^ > 1 warning generated. > > It is not wrong; text has a zero size when CONFIG_PRINTK is disabled > because LOG_LINE_MAX and PREFIX_MAX are both zero. Change to snprintf so > that this case is explicitly handled without any risk of overflow. We probably can add a note here that for !CONFIG_PRINTK builds logbuf overflow is very unlikely. Otherwise, Reviewed-by: Sergey Senozhatsky -ss