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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE265C43334 for ; Fri, 10 Jun 2022 09:22:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 498F16B014C; Fri, 10 Jun 2022 05:22:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 421FA6B014E; Fri, 10 Jun 2022 05:22:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2C3238D0085; Fri, 10 Jun 2022 05:22:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 161426B014C for ; Fri, 10 Jun 2022 05:22:49 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id EA05D6039B for ; Fri, 10 Jun 2022 09:22:48 +0000 (UTC) X-FDA: 79561786416.09.C3DB767 Received: from a3.inai.de (a3.inai.de [88.198.85.195]) by imf19.hostedemail.com (Postfix) with ESMTP id 5A01E1A0073 for ; Fri, 10 Jun 2022 09:22:48 +0000 (UTC) Received: by a3.inai.de (Postfix, from userid 25121) id 7182C5872870F; Fri, 10 Jun 2022 11:22:46 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by a3.inai.de (Postfix) with ESMTP id 70A0760C247D5; Fri, 10 Jun 2022 11:22:46 +0200 (CEST) Date: Fri, 10 Jun 2022 11:22:46 +0200 (CEST) From: Jan Engelhardt To: David Laight cc: 'Bill Wendling' , Andrew Morton , Bill Wendling , Tony Luck , Borislav Petkov , Thomas Gleixner , Ingo Molnar , Dave Hansen , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "H. Peter Anvin" , Phillip Potter , Arnd Bergmann , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jan Kara , Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jaroslav Kysela , Takashi Iwai , Nathan Chancellor , Nick Desaulniers , Tom Rix , Ross Philipson , Daniel Kiper , "linux-edac@vger.kernel.org" , LKML , ACPI Devel Maling List , "linux-mm@kvack.org" , "netfilter-devel@vger.kernel.org" , "coreteam@netfilter.org" , Networking , "alsa-devel@alsa-project.org" , clang-built-linux Subject: RE: [PATCH 00/12] Clang -Wformat warning fixes In-Reply-To: <724889aa6a8d4d41b8557733610c7657@AcuMS.aculab.com> Message-ID: References: <20220609221702.347522-1-morbo@google.com> <20220609152527.4ad7862d4126e276e6f76315@linux-foundation.org> <01da36bfd13e421aadb2eff661e7a959@AcuMS.aculab.com> <724889aa6a8d4d41b8557733610c7657@AcuMS.aculab.com> User-Agent: Alpine 2.25 (LSU 592 2021-09-18) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1654852968; a=rsa-sha256; cv=none; b=D0xejR2inwzlRcjMetSrIhy3h5INEXzJsnAPxGIgrXZyR7pKr3guslDnbY75pEXSHXPx0X VmpBteNA48T44w4GWwtXFzlIcNSTEhyhQ53cr7r8tezXj4UVjaA0ezYG+BDNGOm3DCwUxs DT5iTiKTATcP7jJd4vZptTSwtoAMgOU= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of jengelh@inai.de designates 88.198.85.195 as permitted sender) smtp.mailfrom=jengelh@inai.de; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1654852968; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WZjj1Of6WPSX5FyLjQvJ+YXcFxWE/AFSY85ZlhirO9s=; b=18ps9lPcJ2Lzmfvl64n/h7ljZbarofjAVOxYphnGrrUBH+f8d14log2pBJC9A1qIrukChQ mP9KZVTXxuILilaFb8pfT+348I+DXcugA9nTHlg2Uw+O/ZYqISBUlZYg1H1C7LADeevpKb dwm3HfNieiGSVTfeqeUWxZsqVJ30KgU= X-Rspamd-Queue-Id: 5A01E1A0073 X-Rspam-User: Authentication-Results: imf19.hostedemail.com; dkim=none; spf=pass (imf19.hostedemail.com: domain of jengelh@inai.de designates 88.198.85.195 as permitted sender) smtp.mailfrom=jengelh@inai.de; dmarc=none X-Stat-Signature: eb8ygdbbidtqsfun635fzopek6nu8zs5 X-Rspamd-Server: rspam02 X-HE-Tag: 1654852968-969421 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Friday 2022-06-10 11:14, David Laight wrote: >> >Yep, IMHO definitely should be fixed. >> >It is even possible that using "%s" is faster because the printf >> >code doesn't have to scan the string for format effectors. >> >> I see no special handling; the vsnprintf function just loops >> over fmt as usual and I see no special casing of fmt by >> e.g. strcmp(fmt, "%s") == 0 to take a shortcut. > >Consider the difference between: > printf("fubar"); >and > printf("%s", "fubar"); >In the former all of "fubar" is checked for '%'. >In the latter only the length of "fubar" has to be counted. To check the length of "fubar", printf first needs to know that there even is an argument to be pulled from the stack, which it does by evaluating the format string. So, in fairness, it's more like: >> In the latter, all of "%s" is checked for '%'.