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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5E13C433F5 for ; Wed, 4 May 2022 13:36:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350692AbiEDNkW (ORCPT ); Wed, 4 May 2022 09:40:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350674AbiEDNkQ (ORCPT ); Wed, 4 May 2022 09:40:16 -0400 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [IPv6:2a00:1450:4864:20::42c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A99893B549 for ; Wed, 4 May 2022 06:36:39 -0700 (PDT) Received: by mail-wr1-x42c.google.com with SMTP id u3so2076414wrg.3 for ; Wed, 04 May 2022 06:36:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:content-language:to:from :subject:cc:content-transfer-encoding; bh=bu++xSk9S8GRGmlH5GsI6es9SClwEAo1FD6rz8cK+go=; b=fRnO9sm54iS/qr621PjI32v6sWAjMqv01u1e2HCln/DGaL71KodkjRYM1YVfIPUzv3 JuNBJznV4KaGgYxqNOUz7jhmFaR/YPKo39OlP9xkvI0moqtXVthBUQta4Be3Fo0OT0dB 8KibqYbJOMu9URA4eOElG0ojLnz1bfktw1pCULwiqS6WT6Y7PmavmtUhqd1ESFB2iArG PyjnhX5dhgahbMyDo6p9Xoblyfi640BvRPzLL+tWsliEH6poR//BwUlr4blcaPR7Cf/c DEaXNPvH0WpYACMg5gXaVoL+P6u/LhrPhZxPiacw+4GFT6CZgBYSZCyzPq1Hy72JJoJj 3wIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:from:subject:cc:content-transfer-encoding; bh=bu++xSk9S8GRGmlH5GsI6es9SClwEAo1FD6rz8cK+go=; b=HuUcKM6mAVc9BFzIPbYLqyFab2NKukkCLqx/Zm9U/Jkjs50PyTJRCcETzCSmcoQKxz gDxHZXONAAdrSTfA/f7qOE5gNtCooc0hGjzZAreYFPIgBQdbd5Iz8I3fOVU8CT9OOK6g Hwv1C3TJiVCSv1qecATS3IUmY7uHdcreojD+BWWuXYDhEviC3XpN3j2DICffrFjB0fom iB7Xy3wVR802VZ/SlfwCWWyTh89ug5U0wZjK6+AZFfLeDSuKySvvDTtrrftdFKgiiFVb 9pQm5IEdrpyNDvwOF/8vneXKFcuC0ad3DbgiPmMyfQOmX8Rc9SnaFL/gWH8cynhTEycy qXgA== X-Gm-Message-State: AOAM532B+BMId1FjjRm3Makmp/CBSKC6pkcSOmIhyEf7kZrq3ixkkg7u zJdbAVCHvNf2/UV2EqHZll4= X-Google-Smtp-Source: ABdhPJykRbvC4+oHRIq6O3oIuG2ht/akttjtjdQ8Xf8QUi04ZuSc2/tpAKwlbVXS+7gojwdWoiVYEw== X-Received: by 2002:a5d:414a:0:b0:20a:d5f9:8b62 with SMTP id c10-20020a5d414a000000b0020ad5f98b62mr16875525wrq.492.1651671397953; Wed, 04 May 2022 06:36:37 -0700 (PDT) Received: from [192.168.0.210] (cpc154979-craw9-2-0-cust193.16-3.cable.virginm.net. [80.193.200.194]) by smtp.googlemail.com with ESMTPSA id h29-20020adfaa9d000000b0020c5253d913sm11597769wrc.95.2022.05.04.06.36.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 May 2022 06:36:37 -0700 (PDT) Message-ID: <9a206b6b-bb60-b86b-666d-c75748237cf0@gmail.com> Date: Wed, 4 May 2022 14:36:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Content-Language: en-US To: Andrew Morton , Linux-MM , Hugh Dickins , "Matthew Wilcox (Oracle)" From: "Colin King (gmail)" Subject: re: mm/shmem: turn shmem_alloc_page() into shmem_alloc_folio() Cc: "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Static analysis with clang scan-build found an issue in the following commit: commit b0bb08b2d5f399369a906eff0287e64b531881d8 Author: Matthew Wilcox (Oracle) Date: Fri Apr 29 14:43:02 2022 -0700 mm/shmem: turn shmem_alloc_page() into shmem_alloc_folio() The issue is as follows: #ifdef CONFIG_USERFAULTFD int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, struct vm_area_struct *dst_vma, unsigned long dst_addr, unsigned long src_addr, bool zeropage, bool wp_copy, struct page **pagep) { struct inode *inode = file_inode(dst_vma->vm_file); struct shmem_inode_info *info = SHMEM_I(inode); struct address_space *mapping = inode->i_mapping; gfp_t gfp = mapping_gfp_mask(mapping); pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); void *page_kaddr; struct folio *folio; struct page *page; ^^ page is not intialized int ret; pgoff_t max_off; if (!shmem_inode_acct_block(inode, 1)) { /* * We may have got a page, returned -ENOENT triggering a retry, * and now we find ourselves with -ENOMEM. Release the page, to * avoid a BUG_ON in our caller. */ if (unlikely(*pagep)) { put_page(*pagep); *pagep = NULL; } return -ENOMEM; } if (!*pagep) { ret = -ENOMEM; if (!page) goto out_unacct_blocks; ^^ page is being referenced but it has not been set The commit in question removed the assignment to page: if (!*pagep) { ret = -ENOMEM; - page = shmem_alloc_page(gfp, info, pgoff); if (!page) goto out_unacct_blocks; Colin