From patchwork Fri Jun 18 12:51:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 12331275 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA5CDC48BDF for ; Fri, 18 Jun 2021 12:51:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 63EFA61040 for ; Fri, 18 Jun 2021 12:51:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63EFA61040 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F094D6B0070; Fri, 18 Jun 2021 08:51:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EBB506B0071; Fri, 18 Jun 2021 08:51:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5B736B0072; Fri, 18 Jun 2021 08:51:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0057.hostedemail.com [216.40.44.57]) by kanga.kvack.org (Postfix) with ESMTP id A12A96B0070 for ; Fri, 18 Jun 2021 08:51:06 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3C48F8249980 for ; Fri, 18 Jun 2021 12:51:06 +0000 (UTC) X-FDA: 78266829732.04.4E7C5F0 Received: from outbound-smtp16.blacknight.com (outbound-smtp16.blacknight.com [46.22.139.233]) by imf13.hostedemail.com (Postfix) with ESMTP id 69342E0004D9 for ; Fri, 18 Jun 2021 12:51:04 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail05.blacknight.ie [81.17.254.26]) by outbound-smtp16.blacknight.com (Postfix) with ESMTPS id 293C61C3E43 for ; Fri, 18 Jun 2021 13:51:04 +0100 (IST) Received: (qmail 32760 invoked from network); 18 Jun 2021 12:51:03 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.17.255]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 18 Jun 2021 12:51:03 -0000 Date: Fri, 18 Jun 2021 13:51:02 +0100 From: Mel Gorman To: Andrew Morton Cc: Dan Carpenter , Jesper Dangaard Brouer , Vlastimil Babka , Linux-MM , LKML , Mel Gorman Subject: [PATCH] mm/page_alloc: do bulk array bounds check after checking populated elements Message-ID: <20210618125102.GU30378@techsingularity.net> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Authentication-Results: imf13.hostedemail.com; dkim=none; spf=pass (imf13.hostedemail.com: domain of mgorman@techsingularity.net designates 46.22.139.233 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net; dmarc=none X-Stat-Signature: bya3bba7mqe6mg53ifdsfep8wwbj649p X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 69342E0004D9 X-HE-Tag: 1624020664-677730 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: Dan Carpenter reported the following The patch 0f87d9d30f21: "mm/page_alloc: add an array-based interface to the bulk page allocator" from Apr 29, 2021, leads to the following static checker warning: mm/page_alloc.c:5338 __alloc_pages_bulk() warn: potentially one past the end of array 'page_array[nr_populated]' The problem can occur if an array is passed in that is fully populated. That potentially ends up allocating a single page and storing it past the end of the array. This patch returns 0 if the array is fully populated. Fixes: 0f87d9d30f21 ("mm/page_alloc: add an array-based interface to the bulk page allocator") Reported-by: Dan Carpenter Signed-off-by: Mel Gorman --- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7124bb00219d..ef2265f86b91 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5056,6 +5056,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, while (page_array && nr_populated < nr_pages && page_array[nr_populated]) nr_populated++; + /* Already populated array? */ + if (unlikely(page_array && nr_pages - nr_populated == 0)) + return 0; + /* Use the single page allocator for one page. */ if (nr_pages - nr_populated == 1) goto failed;