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 08E28C433F5 for ; Mon, 31 Jan 2022 02:58:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 584A66B00A2; Sun, 30 Jan 2022 21:58:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5335F6B00A3; Sun, 30 Jan 2022 21:58:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3D4D76B00A4; Sun, 30 Jan 2022 21:58:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0019.hostedemail.com [216.40.44.19]) by kanga.kvack.org (Postfix) with ESMTP id 2B5606B00A2 for ; Sun, 30 Jan 2022 21:58:49 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D58638249980 for ; Mon, 31 Jan 2022 02:58:48 +0000 (UTC) X-FDA: 79089074736.22.35EA4E4 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by imf23.hostedemail.com (Postfix) with ESMTP id 796F4140004 for ; Mon, 31 Jan 2022 02:58:48 +0000 (UTC) Received: by mail-pj1-f54.google.com with SMTP id g11-20020a17090a7d0b00b001b2c12c7273so11170255pjl.0 for ; Sun, 30 Jan 2022 18:58:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=UKwameRoPfgLHWpBXoqOSY31hKTED2y4WM3/cMREqYQ=; b=ie36z+3JbZH6BpcGWoA8u8BouUWN7xsL3fl1f4YoG1CTP82izOviQ8uJeRSWesrmi0 SdWI6A0H7yGOF4A02a4ZCDGnvB8dgzI0l6WNB2l6lcim35Ft20EXinLNlIA2m0HzJZro iWeB2iq9vReukiu+pPL2Qswox9STXWvm1FfDc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=UKwameRoPfgLHWpBXoqOSY31hKTED2y4WM3/cMREqYQ=; b=6ov0ceCEfnmB/PwC2Zer0lvV3z8KRXsuup8RiffQI5hDafxXBFlHNSmhCUpG+zxWBV EXjuxJCOfVDO7A/Lf7OaLXpcXky3mcp7+TTaTWGdWCbMRQ6UE+JRENe/6IjhOILjqBuU EsIZhSdp+whYVh6O7fd/ZowmkwoLJdnvYBiw+f/GU/I3sB8ZiLT9+XeyD+eo+w87GQtL hWkrHiqGCOe7nXj/ZQ16UNz5nca22hit4FaZCVPeZZd8Lo+LB3FghOVa6K3NPQX2ZSL/ X0b+Nf0QOZiyNG2n2liO2n9nX0ve/KfesKfVgNqzZvFy/407yE50osuzGMN87NxLOuKe idzQ== X-Gm-Message-State: AOAM533m4UpdcXjcfA9GJksRZiAF7BO+mOARBc5YdUIGhZ/yQC/rpDOH OTqimaaWsxR7gOYvWTfhvAzA7g== X-Google-Smtp-Source: ABdhPJzC803twXWB9gJWO7ckQkbQydjauPxbn+wK2Zrz3p/u8T15jAhCVbBRrUJeQ+UwY1smWH5+XA== X-Received: by 2002:a17:90a:ed03:: with SMTP id kq3mr21942288pjb.136.1643597927548; Sun, 30 Jan 2022 18:58:47 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:c6d0:3c7:e220:605c]) by smtp.gmail.com with ESMTPSA id s30sm5169120pfw.63.2022.01.30.18.58.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Jan 2022 18:58:47 -0800 (PST) Date: Mon, 31 Jan 2022 11:58:41 +0900 From: Sergey Senozhatsky To: Waiman Long Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Petr Mladek , Steven Rostedt , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Ira Weiny , Rafael Aquini Subject: Re: [PATCH v2 2/3] mm/page_owner: Use scnprintf() to avoid excessive buffer overrun check Message-ID: References: <20220129205315.478628-1-longman@redhat.com> <20220129205315.478628-3-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220129205315.478628-3-longman@redhat.com> X-Stat-Signature: kaqeehk4f5za4g18348erwuzcatkx35w X-Rspam-User: nil Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=ie36z+3J; spf=pass (imf23.hostedemail.com: domain of senozhatsky@chromium.org designates 209.85.216.54 as permitted sender) smtp.mailfrom=senozhatsky@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 796F4140004 X-HE-Tag: 1643597928-672971 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000015, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On (22/01/29 15:53), Waiman Long wrote: > The snprintf() function can return a length greater than the given > input size. That will require a check for buffer overrun after each > invocation of snprintf(). scnprintf(), on the other hand, will never > return a greater length. By using scnprintf() in selected places, we > can avoid some buffer overrun checks except after stack_depot_snprint() > and after the last snprintf(). > > Signed-off-by: Waiman Long Reviewed-by: Sergey Senozhatsky