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=-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=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 61F5AC56202 for ; Fri, 20 Nov 2020 23:59:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2463F24171 for ; Fri, 20 Nov 2020 23:59:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="A2XF063b" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728051AbgKTX67 (ORCPT ); Fri, 20 Nov 2020 18:58:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:54430 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726587AbgKTX67 (ORCPT ); Fri, 20 Nov 2020 18:58:59 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C690A23A6B; Fri, 20 Nov 2020 23:58:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1605916738; bh=WGtN4N7vfpSGkj+sIoivGQoBpvorEjtY0qDPv8UNmhA=; h=Date:From:To:Subject:From; b=A2XF063boO/rC8Xh9VK93EH1Da99uP2qccRTgyz/R5LN3q9GW5IwfHze4M2F1nX3L nH4yt1vNRxB8F4v5nbUaWURb7Fun6MIWqlFJvaoT1FJg6Ha+ivM6IIRH2gxlVf0l3t M7YVogm898Y/sNnPcrXlf35r1bgWE6cXERrxRzK8= Date: Fri, 20 Nov 2020 15:58:58 -0800 From: akpm@linux-foundation.org To: mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de Subject: + mmmadvise-call-soft_offline_page-without-mf_count_increased.patch added to -mm tree Message-ID: <20201120235858.sT1j0SdM4%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED has been added to the -mm tree. Its filename is mmmadvise-call-soft_offline_page-without-mf_count_increased.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mmmadvise-call-soft_offline_page-without-mf_count_increased.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mmmadvise-call-soft_offline_page-without-mf_count_increased.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,madvise: call soft_offline_page() without MF_COUNT_INCREASED The call to get_user_pages_fast is only to get the pointer to a struct page of a given address, pinning it is memory-poisoning handler's job, so drop the refcount grabbed by get_user_pages_fast(). Note that the target page is still pinned after this put_page() because the current process should have refcount from mapping. Link: https://lkml.kernel.org/r/20201119105716.5962-4-osalvador@suse.de Signed-off-by: Naoya Horiguchi Signed-off-by: Oscar Salvador Signed-off-by: Andrew Morton --- mm/madvise.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) --- a/mm/madvise.c~mmmadvise-call-soft_offline_page-without-mf_count_increased +++ a/mm/madvise.c @@ -900,20 +900,23 @@ static int madvise_inject_error(int beha */ size = page_size(compound_head(page)); + /* + * The get_user_pages_fast() is just to get the pfn of the + * given address, and the refcount has nothing to do with + * what we try to test, so it should be released immediately. + * This is racy but it's intended because the real hardware + * errors could happen at any moment and memory error handlers + * must properly handle the race. + */ + put_page(page); + if (behavior == MADV_SOFT_OFFLINE) { pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n", pfn, start); - ret = soft_offline_page(pfn, MF_COUNT_INCREASED); + ret = soft_offline_page(pfn, 0); } else { pr_info("Injecting memory failure for pfn %#lx at process virtual address %#lx\n", pfn, start); - /* - * Drop the page reference taken by get_user_pages_fast(). In - * the absence of MF_COUNT_INCREASED the memory_failure() - * routine is responsible for pinning the page to prevent it - * from being released back to the page allocator. - */ - put_page(page); ret = memory_failure(pfn, 0); } _ Patches currently in -mm which might be from naoya.horiguchi@nec.com are mmmadvise-call-soft_offline_page-without-mf_count_increased.patch mmhwpoison-remove-mf_count_increased.patch mmhwpoison-remove-flag-argument-from-soft-offline-functions.patch