From patchwork Sat Mar 12 07:46:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12778760 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9E74C433F5 for ; Sat, 12 Mar 2022 07:47:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B9FB98D0001; Sat, 12 Mar 2022 02:47:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AD7448D0003; Sat, 12 Mar 2022 02:47:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 887D68D0005; Sat, 12 Mar 2022 02:47:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id 6960F8D0002 for ; Sat, 12 Mar 2022 02:47:09 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0331A97906 for ; Sat, 12 Mar 2022 07:47:08 +0000 (UTC) X-FDA: 79234953378.24.E606879 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf05.hostedemail.com (Postfix) with ESMTP id 1502E10001E for ; Sat, 12 Mar 2022 07:47:07 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KFvwL60rQzBrYL; Sat, 12 Mar 2022 15:45:06 +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 15.1.2308.21; Sat, 12 Mar 2022 15:47:04 +0800 From: Miaohe Lin To: , , , CC: , , , , , Subject: [PATCH v2 1/3] mm/memory-failure.c: fix race with changing page compound again Date: Sat, 12 Mar 2022 15:46:11 +0800 Message-ID: <20220312074613.4798-2-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220312074613.4798-1-linmiaohe@huawei.com> References: <20220312074613.4798-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1502E10001E X-Stat-Signature: ihmzz8xihd77mt78a8e1pnupcetbo7hf Authentication-Results: imf05.hostedemail.com; dkim=none; spf=pass (imf05.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspam-User: X-HE-Tag: 1647071227-939818 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: There is a race window where we got the compound_head, the hugetlb page could be freed to buddy, or even changed to another compound page just before we try to get hwpoison page. Think about the below race window: CPU 1 CPU 2 memory_failure_hugetlb struct page *head = compound_head(p); hugetlb page might be freed to buddy, or even changed to another compound page. get_hwpoison_page -- page is not what we want now... If this race happens, just bail out. Also MF_MSG_DIFFERENT_PAGE_SIZE is introduced to record this event. Signed-off-by: Miaohe Lin Acked-by: Naoya Horiguchi --- include/linux/mm.h | 1 + include/ras/ras_event.h | 1 + mm/memory-failure.c | 12 ++++++++++++ 3 files changed, 14 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index c9bada4096ac..ef98cff2b253 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3253,6 +3253,7 @@ enum mf_action_page_type { MF_MSG_BUDDY, MF_MSG_DAX, MF_MSG_UNSPLIT_THP, + MF_MSG_DIFFERENT_PAGE_SIZE, MF_MSG_UNKNOWN, }; diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h index d0337a41141c..1e694fd239b9 100644 --- a/include/ras/ras_event.h +++ b/include/ras/ras_event.h @@ -374,6 +374,7 @@ TRACE_EVENT(aer_event, EM ( MF_MSG_BUDDY, "free buddy page" ) \ EM ( MF_MSG_DAX, "dax page" ) \ EM ( MF_MSG_UNSPLIT_THP, "unsplit thp" ) \ + EM ( MF_MSG_DIFFERENT_PAGE_SIZE, "different page size" ) \ EMe ( MF_MSG_UNKNOWN, "unknown page" ) /* diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 5444a8ef4867..dabecd87ad3f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -733,6 +733,7 @@ static const char * const action_page_types[] = { [MF_MSG_BUDDY] = "free buddy page", [MF_MSG_DAX] = "dax page", [MF_MSG_UNSPLIT_THP] = "unsplit thp", + [MF_MSG_DIFFERENT_PAGE_SIZE] = "different page size", [MF_MSG_UNKNOWN] = "unknown page", }; @@ -1534,6 +1535,17 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) } lock_page(head); + + /** + * The page could have changed compound pages due to race window. + * If this happens just bail out. + */ + if (!PageHuge(p) || compound_head(p) != head) { + action_result(pfn, MF_MSG_DIFFERENT_PAGE_SIZE, MF_IGNORED); + res = -EBUSY; + goto out; + } + page_flags = head->flags; if (hwpoison_filter(p)) {