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 5D0F9EB64DD for ; Thu, 3 Aug 2023 15:25:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B20EA280278; Thu, 3 Aug 2023 11:25:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AA9DC28022C; Thu, 3 Aug 2023 11:25:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 92403280278; Thu, 3 Aug 2023 11:25:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 82DA228022C for ; Thu, 3 Aug 2023 11:25:29 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 31B6C121293 for ; Thu, 3 Aug 2023 15:25:29 +0000 (UTC) X-FDA: 81083167578.21.73AF41E Received: from mail-ed1-f45.google.com (mail-ed1-f45.google.com [209.85.208.45]) by imf11.hostedemail.com (Postfix) with ESMTP id 07D1640028 for ; Thu, 3 Aug 2023 15:25:26 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b="1/JqHb/L"; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of emmir@google.com designates 209.85.208.45 as permitted sender) smtp.mailfrom=emmir@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1691076327; 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:dkim-signature; bh=3i6erIjjtN6lPgXcEJaSwL8Ki+NeE4iek/Jz08H42Eg=; b=in1ZX5BmgmBBXfmdwzCaWlAgKMEFgohksXkukmtA0Bya6wrZJPJbzVHh1LeqxXvU46+KUA vdmXEAD+bkAZMZ9TgzvzPvA/+wlWxGQw3g9wuWDYB0MHQf8WNL0Ln2hSFF7Zx1yz/kNSho WM2tgiVkjNEHWRoVoeovSSBKS6t25Wk= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20221208 header.b="1/JqHb/L"; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of emmir@google.com designates 209.85.208.45 as permitted sender) smtp.mailfrom=emmir@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691076327; a=rsa-sha256; cv=none; b=ZcgldGWAsccn+R95+IEtg1bBJd59YvIvbP1MR3t2aeuLvmeRV+lzti+3f3k9pCINTuBmts Vy0HyxlH1XXNBGpIQ8xy0Pvat5fKPDhE4sW10cQ6WSwXHnH8q+P1X2pq+K3ngf+mlBY3/N uk0lXYznsugWoC5dpntCmP0cX/MDinw= Received: by mail-ed1-f45.google.com with SMTP id 4fb4d7f45d1cf-51e24210395so13312a12.0 for ; Thu, 03 Aug 2023 08:25:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1691076325; x=1691681125; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=3i6erIjjtN6lPgXcEJaSwL8Ki+NeE4iek/Jz08H42Eg=; b=1/JqHb/LG7PoqyNlz01wER9UTCkrpH9M2FU4Vbd6r/CQI4UW/uMBfpHnxSvH72WDZa 17EGkY/9+0GvLunkXQuT7Fj49JG1SV574d0CzUHATzQilyCkac+gLSTBBXJIZaVwWa8s cpGdP8Hx/x2GWYeMp4ndHvJGpBnn6RxkjNP6yBq0qKblG8zGXopTU7sKzKEIb2z2fZkO BdPPCqQxqGQIeeNv0DmWgOhQUsoK2E/MGim7smaG3/IvHHUGhOOYRpcldpDLCveM/scO t0H6kHpbTnshhZS2Vd+Rog+eB2YM23VKEVtMN5/XEaDpvaH5k2NGGFIFniZnJgDxkngD M2uQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691076325; x=1691681125; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=3i6erIjjtN6lPgXcEJaSwL8Ki+NeE4iek/Jz08H42Eg=; b=RDCp+h/ml+GBBmWWwvbxdr7yVKq1Honn629wbcUHBfAo2NMQhyqcXACE4Qas/+NhHB wS8fmPOIsILjIkutCgT3A6+NP2Egsg6M4SHbhm6rcDpcS6olWumgNmFWCHddy1bB6XPr UiaZMkkD398jzMfOFHG6CpTwRpeOGQZ96jrbuvsJvbNkbszDTYNXzdJ7FaHisC2tWnlr 7jYR5zI4zZ72BWMguzyf09aNprJ3puSOr3UTiJyFucrqIQrVHBVc1rzX95NMqOWE0rra WcZWeIGkqmbRJxyypyJp2y2ok7cJjkK7SFbAqSsXQ6Rs0o3Q8R1ynn7+vHViu/1c5938 WUjA== X-Gm-Message-State: ABy/qLYiy4WmRvVT7apTcFgHciohryTA6JFBschNqzJyfwY1ExXG3QcG +rl0KH/NhU/pozqCDnllROE4O+iqbtzyxHzo5xtc5A== X-Google-Smtp-Source: APBJJlHEkuDfzpxiBsrJVo+Ct415MwqYT9+g40+EOyv9eJZgbwZFuwhEjHnaDyGp8XxHI0wEbUXhD/X+RM4zDUX956g= X-Received: by 2002:a50:8e16:0:b0:51e:16c5:2004 with SMTP id 22-20020a508e16000000b0051e16c52004mr528078edw.6.1691076325295; Thu, 03 Aug 2023 08:25:25 -0700 (PDT) MIME-Version: 1.0 References: <20230727093637.1262110-1-usama.anjum@collabora.com> <20230727093637.1262110-3-usama.anjum@collabora.com> In-Reply-To: From: =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= Date: Thu, 3 Aug 2023 17:25:13 +0200 Message-ID: Subject: Re: [PATCH v26 2/5] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs To: Andrei Vagin Cc: Muhammad Usama Anjum , Peter Xu , David Hildenbrand , Andrew Morton , Danylo Mocherniuk , Paul Gofman , Cyrill Gorcunov , Mike Rapoport , Nadav Amit , Alexander Viro , Shuah Khan , Christian Brauner , Yang Shi , Vlastimil Babka , "Liam R . Howlett" , Yun Zhou , Suren Baghdasaryan , Alex Sierra , Matthew Wilcox , Pasha Tatashin , Axel Rasmussen , "Gustavo A . R . Silva" , Dan Williams , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Greg KH , kernel@collabora.com, =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 07D1640028 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: p3fdm4g5jz45gmjs4zwydogq3znbpsoa X-HE-Tag: 1691076326-890790 X-HE-Meta: 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 sZmUyMzv 9BR60g7bZIRxqlgEllMr4yj4Ab09ZQE3UIjqe6AMDsHjwKFnfzRV+Y3w/QvIXi0lXuFZDR/yyeifnSu9wS6EtGmx0Ie+zae3LjGVyIiJJ0oX5tzg5ohBZqRQJbEayZkvVNiPYoUYf6RZjHcOwl4syL5oAinUgYPyudL95uxpoNl8oi70OfSflN6au6qgiFmV/F6nacH6OIzEJQc3a1zeaLKJmXIRZ+5/KA2SiHWWCAsz4xA5JboW0DS3x/RAY+JMbj2Q5HeC8p5askdRQBV0xEZ3Zg6/Pe/Ed0wXyjHwrfyN3+cFs5BgRxR0iMz64R6HHq1gq 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 Thu, 3 Aug 2023 at 17:09, Andrei Vagin wrote: > On Thu, Jul 27, 2023 at 02:36:34PM +0500, Muhammad Usama Anjum wrote: [...] > > + n_pages =3D (*end - addr) / PAGE_SIZE; > > + if (check_add_overflow(p->found_pages, n_pages, &total_pages) || > > + total_pages > p->arg.max_pages) { > > why do we need to use check_add_overflow here? > > > + size_t n_too_much =3D total_pages - p->arg.max_pages; > > it is unsafe to use total_pages if check_add_overflow returns non-zero. Since we're adding unsigned integers, this is well defined even after overf= low. Best Regards Micha=C5=82 Miros=C5=82aw