From patchwork Fri Jun 5 14:15:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 224781 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 99F67C433E0 for ; Fri, 5 Jun 2020 14:21:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 616BF20663 for ; Fri, 5 Jun 2020 14:21:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591366903; bh=ZmwBUR7+DZZ6gNJAh78+DU1YLOyaYWC2FmNmChYEAxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=DT/Q0UEQk5jtzKafJkJiCbl89LrqkfZx5PpLZSEq1/HwpLCi1pB7ORZBsMAy66Cse gz9DffvkPga5Zk+LfUGRRZCAgLjPXrAabwCIQHIpLyo4tq+1e9a61IrqtMAVAIM6Pe d+wOmtAVQPSiSJxYmxjYujSHy0g/mM1b0MCh1QTo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728098AbgFEOVm (ORCPT ); Fri, 5 Jun 2020 10:21:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:51190 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728917AbgFEOUE (ORCPT ); Fri, 5 Jun 2020 10:20:04 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 54B28208B6; Fri, 5 Jun 2020 14:20:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591366803; bh=ZmwBUR7+DZZ6gNJAh78+DU1YLOyaYWC2FmNmChYEAxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hrn1HZs13g7Rkm9EG30fVAYmXeLIZtJE7iQc/Cvd9ki36QEvv+wq9TvUoe+ylFjjQ fo+srkZRnqhs7feS/766pq8gWAHWwpYW1b+itwApWS+rYYANbiaD7xEFQtDCFJ9xk6 SyQ4fPATTA9M+P+g/BDxF72TbAR8TBXyrXwne86Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gerald Schaefer , Vasily Gorbik , Sasha Levin Subject: [PATCH 4.19 24/28] s390/mm: fix set_huge_pte_at() for empty ptes Date: Fri, 5 Jun 2020 16:15:26 +0200 Message-Id: <20200605140253.810716415@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200605140252.338635395@linuxfoundation.org> References: <20200605140252.338635395@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Gerald Schaefer [ Upstream commit ac8372f3b4e41015549b331a4f350224661e7fc6 ] On s390, the layout of normal and large ptes (i.e. pmds/puds) differs. Therefore, set_huge_pte_at() does a conversion from a normal pte to the corresponding large pmd/pud. So, when converting an empty pte, this should result in an empty pmd/pud, which would return true for pmd/pud_none(). However, after conversion we also mark the pmd/pud as large, and therefore present. For empty ptes, this will result in an empty pmd/pud that is also marked as large, and pmd/pud_none() would not return true. There is currently no issue with this behaviour, as set_huge_pte_at() does not seem to be called for empty ptes. It would be valid though, so let's fix this by not marking empty ptes as large in set_huge_pte_at(). This was found by testing a patch from from Anshuman Khandual, which is currently discussed on LKML ("mm/debug: Add more arch page table helper tests"). Signed-off-by: Gerald Schaefer Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- arch/s390/mm/hugetlbpage.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index 5674710a4841..7dfae86afa47 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -159,10 +159,13 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, rste &= ~_SEGMENT_ENTRY_NOEXEC; /* Set correct table type for 2G hugepages */ - if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) - rste |= _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE; - else + if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) { + if (likely(pte_present(pte))) + rste |= _REGION3_ENTRY_LARGE; + rste |= _REGION_ENTRY_TYPE_R3; + } else if (likely(pte_present(pte))) rste |= _SEGMENT_ENTRY_LARGE; + clear_huge_pte_skeys(mm, rste); pte_val(*ptep) = rste; }