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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 B16F8C31E44 for ; Wed, 12 Jun 2019 01:49:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9300B20883 for ; Wed, 12 Jun 2019 01:49:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392048AbfFLBtP (ORCPT ); Tue, 11 Jun 2019 21:49:15 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:18131 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729044AbfFLBtP (ORCPT ); Tue, 11 Jun 2019 21:49:15 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id E8849EB679BB46D72185; Wed, 12 Jun 2019 09:49:10 +0800 (CST) Received: from RH5885H-V3.huawei.com (10.90.53.225) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.439.0; Wed, 12 Jun 2019 09:48:57 +0800 From: ZhangXiaoxu To: , , , , , Subject: [PATCH] futex: Fix futex lock the wrong page Date: Wed, 12 Jun 2019 09:54:25 +0800 Message-ID: <1560304465-68966-1-git-send-email-zhangxiaoxu5@huawei.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.90.53.225] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The upstram commit 65d8fc777f6d ("futex: Remove requirement for lock_page() in get_futex_key()") use variable 'page' as the page head, when merge it to stable branch, the variable `page_head` is page head. In the stable branch, the variable `page` not means the page head, when lock the page head, we should lock 'page_head', rather than 'page'. It maybe lead a hung task problem. Signed-off-by: ZhangXiaoxu Cc: stable@vger.kernel.org --- kernel/futex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index ec9df5b..15d850f 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -593,8 +593,8 @@ again: * applies. If this is really a shmem page then the page lock * will prevent unexpected transitions. */ - lock_page(page); - shmem_swizzled = PageSwapCache(page) || page->mapping; + lock_page(page_head); + shmem_swizzled = PageSwapCache(page_head) || page_head->mapping; unlock_page(page_head); put_page(page_head); -- 2.7.4