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 0E504C433EF for ; Mon, 27 Dec 2021 15:48:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239734AbhL0Prz (ORCPT ); Mon, 27 Dec 2021 10:47:55 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:43504 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240146AbhL0Por (ORCPT ); Mon, 27 Dec 2021 10:44:47 -0500 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 59CBF610A2; Mon, 27 Dec 2021 15:44:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41B06C36AEA; Mon, 27 Dec 2021 15:44:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640619884; bh=GVZWDSy7d4AbwiKbYJ1h5Ls7xMXkmzsQC7rQL1OgdZM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mB85GW22H1ehMnzBYEez6QNrNRp4of8pXf1D7j6XlLydgXvbUTwACCdXJlgKHEPfM 5RrCz1KHwzA/uaC4MMG2Y9gO5BYdroB5pcSVVQG/Kb/S3Usts+YH2IkGxxYmnAlyy/ RNmCn+njCCin3U6aaLlaBrsleKWY3GLz7ckcP0lo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naoya Horiguchi , Fei Luo , Mike Kravetz , Andrew Morton , Linus Torvalds Subject: [PATCH 5.15 103/128] mm, hwpoison: fix condition in free hugetlb page path Date: Mon, 27 Dec 2021 16:31:18 +0100 Message-Id: <20211227151334.954562629@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211227151331.502501367@linuxfoundation.org> References: <20211227151331.502501367@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Naoya Horiguchi commit e37e7b0b3bd52ec4f8ab71b027bcec08f57f1b3b upstream. 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__page_handle_poison() is expected to be called to isolate the error in 4kB unit, but it's not called due to the outdated if-condition in memory_failure_hugetlb().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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory-failure.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1437,17 +1437,12 @@ 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;