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 D1F3EC433F5 for ; Thu, 3 Feb 2022 06:27:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 304858D0114; Thu, 3 Feb 2022 01:27:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2B4386B036F; Thu, 3 Feb 2022 01:27:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1A3148D0114; Thu, 3 Feb 2022 01:27:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0216.hostedemail.com [216.40.44.216]) by kanga.kvack.org (Postfix) with ESMTP id 0AA6E6B036E for ; Thu, 3 Feb 2022 01:27:59 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id C08D296779 for ; Thu, 3 Feb 2022 06:27:58 +0000 (UTC) X-FDA: 79100488236.21.1583575 Received: from mail-yb1-f169.google.com (mail-yb1-f169.google.com [209.85.219.169]) by imf28.hostedemail.com (Postfix) with ESMTP id 549E1C0005 for ; Thu, 3 Feb 2022 06:27:58 +0000 (UTC) Received: by mail-yb1-f169.google.com with SMTP id i10so5747219ybt.10 for ; Wed, 02 Feb 2022 22:27:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:from:date:message-id:subject:to:cc; bh=QfWsHpzMv7MOEjkEvoCjQ/ClTe4kUM35UqplmdMDux8=; b=OBMo4dGol6rni5b6HIbWk5iep7kV8XHSEWwdEisb/CFGwbISqKM9cOqNH80tEw/we8 GM0IjMMesVSzsbWAERweOtuYWPsr5Z/25MRCvUfd8+aiBBBgtiZWqZpaEFfEFJA53a4L 61McLr8vButdB0dVzPyoJQvV/LhcNCgcohB18QsiWo4a22iuN2xmPh+BgOYEwK4zv+5n PfI5fshWL59Oxws2+cZppbruB+vcVoulopkaQACbU8w9mzqd0nVQUPx6r9wOHILfgXaH pLEnTdEDbRFR9L8Tt19QfypIikRGUIAGnCEfT+FpNMCle1hKIZUqZ0Y7/veEj1zTeqWe MrIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=QfWsHpzMv7MOEjkEvoCjQ/ClTe4kUM35UqplmdMDux8=; b=Ik546l5n0YJ/N5r53M03RDWPUMjS70ZscjaSizTaTf8uZfaWDM3hw9O/50s+hzoh1Z P8+hxrhlX4yOY1aXU4eVrNRvBMnENlanxCliKqSk4llY9XG56n6ekvIAP8R+YbdjXeW2 fLGoPBpXuVonkX9vxEumhC1UBkX5mX8Lx2d5/MIjkLHxlR+vSfiaTTvmk8Q8W+dzAFlK QdnEMGfjzKXssVq+Vtk/8Ey1FpjN/PX9lPOTM1YkA6MCw48pCvMXwoinJHeJd/Z9AhmT /RUt1jwselr96dbDJn1M7XurQOTH61e5QtdeHC+sVeyg1dF8O7Dna92rm0WMAsXK5rjh 2mFw== X-Gm-Message-State: AOAM530L95T5Q/Qv5DPcI4+weLejH5d3b/8SERHvkhOpBsna5rUf1Tcd kPpXEOqePpgl6lOFIiJjijXclsL9D9jh5mrl6Tg= X-Google-Smtp-Source: ABdhPJy0Hu4ydKHwQYod2o1W54szLZ7k5hXr0PDzOiAj/+6SoJN/icaRyi2aU388GT9SGtkkroNKj4gT9APgtErPUNc= X-Received: by 2002:a25:b003:: with SMTP id q3mr41741638ybf.767.1643869677470; Wed, 02 Feb 2022 22:27:57 -0800 (PST) MIME-Version: 1.0 From: Lukas Bulwahn Date: Thu, 3 Feb 2022 07:27:47 +0100 Message-ID: Subject: Weird code with change "mm/gup: clean up follow_pfn_pte() slightly" To: Andrew Morton , John Hubbard , Linux Kernel Mailing List , Linux-MM Cc: Jason Gunthorpe , Peter Xu , Alex Williamson , Andrea Arcangeli , David Hildenbrand , Jan Kara , Jason Gunthorpe , "Kirill A. Shutemov" Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=OBMo4dGo; spf=pass (imf28.hostedemail.com: domain of lukas.bulwahn@gmail.com designates 209.85.219.169 as permitted sender) smtp.mailfrom=lukas.bulwahn@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: nil X-Rspamd-Queue-Id: 549E1C0005 X-Stat-Signature: dsbhca73kocmurn6nfs5ydcndd8m9a1a X-Rspamd-Server: rspam12 X-HE-Tag: 1643869678-559812 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000066, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Dear John, Your change "mm/gup: clean up follow_pfn_pte() slightly" (see Link), visible in linux-next as commit 05fef840b5c6 ("mm/gup: clean up follow_pfn_pte() slightly"), is somehow weird. In the new branch if (pages), you set page = ERR_PTR(-EFAULT) and goto out. However, at the label out, the value of page is not used, but the return uses the variables i and ret. Static analysis tools, such as clang-analyzer, rightfully complain about such weird code. Maybe you can have another look at what you intended to set in the branch of that commit or if you intend to jump to the label out? Best regards, Lukas Link: https://lkml.kernel.org/r/20220201101108.306062-3-jhubbard@nvidia.com