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 X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT 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 86AB2C433E0 for ; Fri, 7 Aug 2020 09:14:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5490521744 for ; Fri, 7 Aug 2020 09:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727981AbgHGJOb (ORCPT ); Fri, 7 Aug 2020 05:14:31 -0400 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:35184 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726979AbgHGJOb (ORCPT ); Fri, 7 Aug 2020 05:14:31 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R971e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0U5.Byex_1596791596; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U5.Byex_1596791596) by smtp.aliyun-inc.com(127.0.0.1); Fri, 07 Aug 2020 17:13:16 +0800 From: Wei Yang To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wei Yang Subject: [PATCH 02/10] mm/hugetlb: make sure to get NULL when list is empty Date: Fri, 7 Aug 2020 17:12:43 +0800 Message-Id: <20200807091251.12129-3-richard.weiyang@linux.alibaba.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20200807091251.12129-1-richard.weiyang@linux.alibaba.com> References: <20200807091251.12129-1-richard.weiyang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org list_first_entry() may not return NULL even when the list is empty. Let's make sure the behavior by using list_first_entry_or_null(), otherwise it would corrupt the list. Signed-off-by: Wei Yang --- mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 62ec74f6d03f..0a2f3851b828 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -237,7 +237,8 @@ get_file_region_entry_from_cache(struct resv_map *resv, long from, long to) VM_BUG_ON(resv->region_cache_count <= 0); resv->region_cache_count--; - nrg = list_first_entry(&resv->region_cache, struct file_region, link); + nrg = list_first_entry_or_null(&resv->region_cache, + struct file_region, link); VM_BUG_ON(!nrg); list_del(&nrg->link); -- 2.20.1 (Apple Git-117)