From patchwork Tue May 11 21:13:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 434811 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 93505C43461 for ; Tue, 11 May 2021 21:13:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DEA361927 for ; Tue, 11 May 2021 21:13:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230005AbhEKVO4 (ORCPT ); Tue, 11 May 2021 17:14:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:57720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230002AbhEKVOx (ORCPT ); Tue, 11 May 2021 17:14:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 53C40613C1; Tue, 11 May 2021 21:13:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620767608; bh=FaNqLXn0xP+HfLPemhVvI3HjnZNesqWTpZFJgCh7Zg4=; h=Date:From:To:Subject:From; b=T6P9+S7gipP0bjOp+fzbAWbZRv94ckRkkIQXpTuFrVTwS30mzwnmya5xvGaUu/kTI H69NG/X0dOI241HsBWotVr1iAyEjXerjD2Ecat+My1YIJT4YIIAjIhQgdYULNbSEB0 DOIheqA0MWiOQUF8KBmH2fqQr2EFK7sNhi/5NYJU= Date: Tue, 11 May 2021 14:13:27 -0700 From: akpm@linux-foundation.org To: mhocko@suse.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, songmuchun@bytedance.com, stable@vger.kernel.org, tony.luck@intel.com Subject: + mmhwpoison-fix-race-with-compound-page-allocation.patch added to -mm tree Message-ID: <20210511211327.ac1sYg2xy%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm,hwpoison: fix race with compound page allocation has been added to the -mm tree. Its filename is mmhwpoison-fix-race-with-compound-page-allocation.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mmhwpoison-fix-race-with-compound-page-allocation.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mmhwpoison-fix-race-with-compound-page-allocation.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Naoya Horiguchi Subject: mm,hwpoison: fix race with compound page allocation When hugetlb page fault (under overcommiting situation) and memory_failure() race, VM_BUG_ON_PAGE() is triggered by the following race: CPU0: CPU1: gather_surplus_pages() page = alloc_surplus_huge_page() memory_failure_hugetlb() get_hwpoison_page(page) __get_hwpoison_page(page) get_page_unless_zero(page) zero = put_page_testzero(page) VM_BUG_ON_PAGE(!zero, page) enqueue_huge_page(h, page) put_page(page) __get_hwpoison_page() only checks page refcount before taking additional one for memory error handling, which is wrong because there's time windows where compound pages have non-zero refcount during initialization. So make __get_hwpoison_page() check page status a bit more for a few types of compound pages. PageSlab() check is added because otherwise "non anonymous thp" path is wrongly chosen. Link: https://lkml.kernel.org/r/20210511151016.2310627-2-nao.horiguchi@gmail.com Fixes: ead07f6a867b ("mm/memory-failure: introduce get_hwpoison_page() for consistent refcount handling") Signed-off-by: Naoya Horiguchi Reported-by: Muchun Song Cc: Michal Hocko Cc: Mike Kravetz Cc: Oscar Salvador Cc: Tony Luck Cc: [5.12+] Signed-off-by: Andrew Morton --- mm/memory-failure.c | 55 +++++++++++++++++++++++++----------------- 1 file changed, 34 insertions(+), 21 deletions(-) --- a/mm/memory-failure.c~mmhwpoison-fix-race-with-compound-page-allocation +++ a/mm/memory-failure.c @@ -960,30 +960,43 @@ static int __get_hwpoison_page(struct pa { struct page *head = compound_head(page); - if (!PageHuge(head) && PageTransHuge(head)) { - /* - * Non anonymous thp exists only in allocation/free time. We - * can't handle such a case correctly, so let's give it up. - * This should be better than triggering BUG_ON when kernel - * tries to touch the "partially handled" page. - */ - if (!PageAnon(head)) { - pr_err("Memory failure: %#lx: non anonymous thp\n", - page_to_pfn(page)); - return 0; - } - } + if (PageCompound(page)) { + if (PageSlab(page)) { + return get_page_unless_zero(page); + } else if (PageHuge(head)) { + int ret = 0; - if (get_page_unless_zero(head)) { - if (head == compound_head(page)) - return 1; - - pr_info("Memory failure: %#lx cannot catch tail\n", - page_to_pfn(page)); - put_page(head); + spin_lock(&hugetlb_lock); + if (!PageHuge(head)) + ret = -EBUSY; + else if (HPageFreed(head) || HPageMigratable(head)) + ret = get_page_unless_zero(head); + spin_unlock(&hugetlb_lock); + return ret; + } else if (PageTransHuge(head)) { + /* + * Non anonymous thp exists only in allocation/free time. We + * can't handle such a case correctly, so let's give it up. + * This should be better than triggering BUG_ON when kernel + * tries to touch the "partially handled" page. + */ + if (!PageAnon(head)) { + pr_err("Memory failure: %#lx: non anonymous thp\n", + page_to_pfn(page)); + return 0; + } + if (get_page_unless_zero(head)) { + if (head == compound_head(page)) + return 1; + pr_info("Memory failure: %#lx cannot catch tail\n", + page_to_pfn(page)); + put_page(head); + } + } + return 0; } - return 0; + return get_page_unless_zero(page); } /*