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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D46A0C43334 for ; Fri, 8 Jul 2022 00:54:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236343AbiGHAyh (ORCPT ); Thu, 7 Jul 2022 20:54:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236411AbiGHAya (ORCPT ); Thu, 7 Jul 2022 20:54:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0330770E76 for ; Thu, 7 Jul 2022 17:54:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 96D6561338 for ; Fri, 8 Jul 2022 00:54:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF28BC341C0; Fri, 8 Jul 2022 00:54:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1657241668; bh=Crk+koDlJsdLzKWgSLFKcQA+reDyU/s7fPa9saQse/s=; h=Date:To:From:Subject:From; b=d04WoQuFGPqwJzPE9zkfov6WCmECTBNEFS7o5zX5aLa7KTyyTrl+Hqf33vrWgywe4 f/j9jo79K3azq+AH8N2EbT5TUIOUfxURnTvfFPqpv8ayPk8xKJcabbB2UvyjLphpbF LJS/9PxJzx8qgZvpwWwvcAA0bRpc6LAbDCHCEj4Y= Date: Thu, 07 Jul 2022 17:54:27 -0700 To: mm-commits@vger.kernel.org, songmuchun@bytedance.com, shy828301@gmail.com, osalvador@suse.de, mike.kravetz@oracle.com, liushixin2@huawei.com, linmiaohe@huawei.com, david@redhat.com, naoya.horiguchi@nec.com, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch removed from -mm tree Message-Id: <20220708005427.EF28BC341C0@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage has been removed from the -mm tree. Its filename was mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Naoya Horiguchi Subject: mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage Date: Mon, 4 Jul 2022 10:33:11 +0900 Currently if memory_failure() (modified to remove blocking code with subsequent patch) is called on a page in some 1GB hugepage, memory error handling fails and the raw error page gets into leaked state. The impact is small in production systems (just leaked single 4kB page), but this limits the testability because unpoison doesn't work for it. We can no longer create 1GB hugepage on the 1GB physical address range with such leaked pages, that's not useful when testing on small systems. When a hwpoison page in a 1GB hugepage is handled, it's caught by the PageHWPoison check in free_pages_prepare() because the 1GB hugepage is broken down into raw error pages before coming to this point: if (unlikely(PageHWPoison(page)) && !order) { ... return false; } Then, the page is not sent to buddy and the page refcount is left 0. Originally this check is supposed to work when the error page is freed from page_handle_poison() (that is called from soft-offline), but now we are opening another path to call it, so the callers of __page_handle_poison() need to handle the case by considering the return value 0 as success. Then page refcount for hwpoison is properly incremented so unpoison works. Link: https://lkml.kernel.org/r/20220704013312.2415700-9-naoya.horiguchi@linux.dev Signed-off-by: Naoya Horiguchi Reviewed-by: Miaohe Lin Cc: David Hildenbrand Cc: Liu Shixin Cc: Mike Kravetz Cc: Muchun Song Cc: Oscar Salvador Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/memory-failure.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/mm/memory-failure.c~mm-hwpoison-skip-raw-hwpoison-page-in-freeing-1gb-hugepage +++ a/mm/memory-failure.c @@ -1084,7 +1084,6 @@ static int me_huge_page(struct page_stat res = truncate_error_page(hpage, page_to_pfn(p), mapping); unlock_page(hpage); } else { - res = MF_FAILED; unlock_page(hpage); /* * migration entry prevents later access on error hugepage, @@ -1092,9 +1091,11 @@ static int me_huge_page(struct page_stat * subpages. */ put_page(hpage); - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } } @@ -1855,10 +1856,11 @@ retry: */ if (res == 0) { unlock_page(head); - res = MF_FAILED; - if (__page_handle_poison(p) > 0) { + if (__page_handle_poison(p) >= 0) { page_ref_inc(p); res = MF_RECOVERED; + } else { + res = MF_FAILED; } action_result(pfn, MF_MSG_FREE_HUGE, res); return res == MF_RECOVERED ? 0 : -EBUSY; _ Patches currently in -mm which might be from naoya.horiguchi@nec.com are mm-hugetlb-separate-path-for-hwpoison-entry-in-copy_hugetlb_page_range.patch mm-hwpoison-enable-memory-error-handling-on-1gb-hugepage.patch