From patchwork Sat Dec 25 05:12:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 528139 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 AECE8C433EF for ; Sat, 25 Dec 2021 05:12:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229806AbhLYFMt (ORCPT ); Sat, 25 Dec 2021 00:12:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbhLYFMs (ORCPT ); Sat, 25 Dec 2021 00:12:48 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3814C061401; Fri, 24 Dec 2021 21:12:48 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id 606E4B80939; Sat, 25 Dec 2021 05:12:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D675CC36AE5; Sat, 25 Dec 2021 05:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1640409166; bh=t1cKdzqXaN9juD51UD8CmyrMzm8EciQHDZMKnzSa3xk=; h=Date:From:To:Subject:In-Reply-To:From; b=oCc7X0JSK/XViToPutcUMR93WkiTlosKmOMselPvWweQ2xfsRlGV4fhngKzO5/Dq4 MD6PoyAvEnmImr1kTzCKxK7ekbdOKYmcNbOizFOTsEUSWcbBnhoSUnQsux2tJ/RDOA 0gXNN6ZQ3NTBafwGxAHzE6sgdfO2CqiKSsatZU58= Date: Fri, 24 Dec 2021 21:12:45 -0800 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, luofei@unicloud.com, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 5/9] mm, hwpoison: fix condition in free hugetlb page path Message-ID: <20211225051245.qaFlHGVIZ%akpm@linux-foundation.org> In-Reply-To: <20211224211127.30b60764d059ff3b0afea38a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Naoya Horiguchi Subject: mm, hwpoison: fix condition in free hugetlb page path When a memory error hits a tail page of a free hugepage, __page_handle_poison() is expected to be called to isolate the error in 4kB unit, but it's not called due to the outdated if-condition in memory_failure_hugetlb(). This loses the chance to isolate the error in the finer unit, so it's not optimal. Drop the condition. This "(p != head && TestSetPageHWPoison(head)" condition is based on the old semantics of PageHWPoison on hugepage (where PG_hwpoison flag was set on the subpage), so it's not necessray any more. By getting to set PG_hwpoison on head page for hugepages, concurrent error events on different subpages in a single hugepage can be prevented by TestSetPageHWPoison(head) at the beginning of memory_failure_hugetlb(). So dropping the condition should not reopen the race window originally mentioned in commit b985194c8c0a ("hwpoison, hugetlb: lock_page/unlock_page does not match for handling a free hugepage") [naoya.horiguchi@linux.dev: fix "HardwareCorrupted" counter] Link: https://lkml.kernel.org/r/20211220084851.GA1460264@u2004 Link: https://lkml.kernel.org/r/20211210110208.879740-1-naoya.horiguchi@linux.dev Signed-off-by: Naoya Horiguchi Reported-by: Fei Luo Reviewed-by: Mike Kravetz Cc: [5.14+] Signed-off-by: Andrew Morton --- mm/memory-failure.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) --- a/mm/memory-failure.c~mm-hwpoison-fix-condition-in-free-hugetlb-page-path +++ a/mm/memory-failure.c @@ -1470,17 +1470,12 @@ static int memory_failure_hugetlb(unsign if (!(flags & MF_COUNT_INCREASED)) { res = get_hwpoison_page(p, flags); if (!res) { - /* - * Check "filter hit" and "race with other subpage." - */ lock_page(head); - if (PageHWPoison(head)) { - if ((hwpoison_filter(p) && TestClearPageHWPoison(p)) - || (p != head && TestSetPageHWPoison(head))) { + if (hwpoison_filter(p)) { + if (TestClearPageHWPoison(head)) num_poisoned_pages_dec(); - unlock_page(head); - return 0; - } + unlock_page(head); + return 0; } unlock_page(head); res = MF_FAILED;