From nobody Tue Feb 10 12:40:37 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 EF83CEB64DA for ; Sat, 8 Jul 2023 08:57:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229788AbjGHI5x (ORCPT ); Sat, 8 Jul 2023 04:57:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbjGHI5g (ORCPT ); Sat, 8 Jul 2023 04:57:36 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1968A2114 for ; Sat, 8 Jul 2023 01:57:35 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Qykbc53xHztQnv; Sat, 8 Jul 2023 16:54:36 +0800 (CST) Received: from huawei.com (10.174.151.185) 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 15.1.2507.27; Sat, 8 Jul 2023 16:57:31 +0800 From: Miaohe Lin To: , CC: , , Subject: [PATCH 7/8] mm: memory-failure: fetch compound head after extra page refcnt is held Date: Sat, 8 Jul 2023 16:57:43 +0800 Message-ID: <20230708085744.3599311-8-linmiaohe@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20230708085744.3599311-1-linmiaohe@huawei.com> References: <20230708085744.3599311-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.174.151.185] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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" Page might become thp, huge page or being splited after compound head is fetched but before page refcnt is bumped. So hpage might be a tail page leading to VM_BUG_ON_PAGE(PageTail(page)) in PageTransHuge(). Fixes: 415c64c1453a ("mm/memory-failure: split thp earlier in memory error = handling") Signed-off-by: Miaohe Lin Acked-by: Naoya Horiguchi --- mm/memory-failure.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 0f93175ed862..76d88d27cdbe 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2179,8 +2179,6 @@ int memory_failure(unsigned long pfn, int flags) goto unlock_mutex; } =20 - hpage =3D compound_head(p); - /* * We need/can do nothing about count=3D0 pages. * 1) it's a free page, and therefore in safe hand: @@ -2219,6 +2217,7 @@ int memory_failure(unsigned long pfn, int flags) } } =20 + hpage =3D compound_head(p); if (PageTransHuge(hpage)) { /* * The flag must be set after the refcount is bumped --=20 2.33.0