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,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 EF76EC433C1 for ; Tue, 23 Mar 2021 13:56:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9F326199F for ; Tue, 23 Mar 2021 13:56:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231609AbhCWNzl (ORCPT ); Tue, 23 Mar 2021 09:55:41 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:14856 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231901AbhCWNy6 (ORCPT ); Tue, 23 Mar 2021 09:54:58 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4F4Xr93QBxz92yY; Tue, 23 Mar 2021 21:52:57 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.498.0; Tue, 23 Mar 2021 21:54:46 +0800 From: Miaohe Lin To: CC: , , , , , , , Subject: [PATCH v2 5/5] mm/migrate.c: fix potential deadlock in NUMA balancing shared exec THP case Date: Tue, 23 Mar 2021 09:54:05 -0400 Message-ID: <20210323135405.65059-6-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20210323135405.65059-1-linmiaohe@huawei.com> References: <20210323135405.65059-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 balancing") 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 5357a8527ca2..68bfa1625898 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2192,9 +2192,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, int page_lru = page_is_file_lru(page); unsigned long start = address & HPAGE_PMD_MASK; - if (is_shared_exec_page(vma, page)) - goto out; - new_page = alloc_pages_node(node, (GFP_TRANSHUGE_LIGHT | __GFP_THISNODE), HPAGE_PMD_ORDER); @@ -2306,7 +2303,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm, out_unlock: unlock_page(page); -out: put_page(page); return 0; } -- 2.19.1