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=-16.8 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_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 066B7C433C1 for ; Sat, 20 Mar 2021 09:38:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9355E61964 for ; Sat, 20 Mar 2021 09:38:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9355E61964 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2A3288D0015; Sat, 20 Mar 2021 05:38:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1B5B28D0014; Sat, 20 Mar 2021 05:38:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E3B4C8D0015; Sat, 20 Mar 2021 05:38:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0111.hostedemail.com [216.40.44.111]) by kanga.kvack.org (Postfix) with ESMTP id BE7538D000A for ; Sat, 20 Mar 2021 05:38:04 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 740AF824999B for ; Sat, 20 Mar 2021 09:38:04 +0000 (UTC) X-FDA: 77939751288.10.A6922F2 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) by imf27.hostedemail.com (Postfix) with ESMTP id DAAE180192D5 for ; Sat, 20 Mar 2021 09:38:03 +0000 (UTC) Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4F2bH71zxzz919q; Sat, 20 Mar 2021 17:36:03 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.498.0; Sat, 20 Mar 2021 17:37:51 +0800 From: Miaohe Lin To: CC: , , , , Subject: [PATCH 5/5] mm/migrate.c: fix potential deadlock in NUMA balancing shared exec THP case Date: Sat, 20 Mar 2021 05:37:01 -0400 Message-ID: <20210320093701.12829-6-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20210320093701.12829-1-linmiaohe@huawei.com> References: <20210320093701.12829-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected X-Stat-Signature: yofdq9ts8q1fn6nk14p1gsziis9jc9od X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DAAE180192D5 Received-SPF: none (huawei.com>: No applicable sender policy available) receiver=imf27; identity=mailfrom; envelope-from=""; helo=szxga07-in.huawei.com; client-ip=45.249.212.35 X-HE-DKIM-Result: none/none X-HE-Tag: 1616233083-148643 Content-Transfer-Encoding: quoted-printable 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: Since commit c77c5cbafe54 ("mm: migrate: skip shared exec THP for NUMA balancing"), the NUMA balancing would skip shared exec transhuge page. But this enhancement is not suitable for transhuge page. Because it's required that page_mapcount() must be 1 due to no migration pte dance is done here. On the other hand, the shared exec transhuge page will leave the migrate_misplaced_page() with pte entry untouched and page locked. Thus pagefault for NUMA will be triggered again and deadlock occurs when we start waiting for the page lock held by ourselves. Fixes: c77c5cbafe54 ("mm: migrate: skip shared exec THP for NUMA balancin= g") Signed-off-by: Miaohe Lin --- mm/migrate.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 3e169b72d7b2..67a941c52b6d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2192,9 +2192,6 @@ int migrate_misplaced_transhuge_page(struct mm_stru= ct *mm, int page_lru =3D page_is_file_lru(page); unsigned long start =3D address & HPAGE_PMD_MASK; =20 - if (is_shared_exec_page(vma, page)) - goto out; - new_page =3D alloc_pages_node(node, (GFP_TRANSHUGE_LIGHT | __GFP_THISNODE), HPAGE_PMD_ORDER); @@ -2306,7 +2303,6 @@ int migrate_misplaced_transhuge_page(struct mm_stru= ct *mm, =20 out_unlock: unlock_page(page); -out: put_page(page); return 0; } --=20 2.19.1