From nobody Mon Apr 6 07:49:44 2026 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 D7341C6FA90 for ; Fri, 16 Sep 2022 07:23:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229539AbiIPHX4 (ORCPT ); Fri, 16 Sep 2022 03:23:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230201AbiIPHXl (ORCPT ); Fri, 16 Sep 2022 03:23:41 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6CA1A50DD for ; Fri, 16 Sep 2022 00:23:40 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MTQRT18CRzMmx1; Fri, 16 Sep 2022 15:19:01 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 16 Sep 2022 15:23:38 +0800 From: Miaohe Lin To: , , , CC: , , , Subject: [PATCH v2 06/16] mm/page_alloc: fix freeing static percpu memory Date: Fri, 16 Sep 2022 15:22:47 +0800 Message-ID: <20220916072257.9639-7-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220916072257.9639-1-linmiaohe@huawei.com> References: <20220916072257.9639-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The size of struct per_cpu_zonestat can be 0 on !SMP && !NUMA. In that case, zone->per_cpu_zonestats will always equal to boot_zonestats. But in zone_pcp_reset(), zone->per_cpu_zonestats is freed via free_percpu() directly without checking against boot_zonestats first. boot_zonestats will be released by free_percpu() unexpectedly. Fixes: 28f836b6777b ("mm/page_alloc: split per cpu page lists and zone stat= s") Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador --- mm/page_alloc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 27ef763bb59f..cad235770948 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -9505,9 +9505,11 @@ void zone_pcp_reset(struct zone *zone) drain_zonestat(zone, pzstats); } free_percpu(zone->per_cpu_pageset); - free_percpu(zone->per_cpu_zonestats); zone->per_cpu_pageset =3D &boot_pageset; - zone->per_cpu_zonestats =3D &boot_zonestats; + if (zone->per_cpu_zonestats !=3D &boot_zonestats) { + free_percpu(zone->per_cpu_zonestats); + zone->per_cpu_zonestats =3D &boot_zonestats; + } } } =20 --=20 2.23.0