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 autolearn=unavailable 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 64C3BC4743E for ; Sat, 5 Jun 2021 03:01:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 470D761403 for ; Sat, 5 Jun 2021 03:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230468AbhFEDDG (ORCPT ); Fri, 4 Jun 2021 23:03:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:52550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230169AbhFEDDF (ORCPT ); Fri, 4 Jun 2021 23:03:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8359D61402; Sat, 5 Jun 2021 03:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1622862078; bh=4bHvHbl6CY5ATZIsrA1xqhEJ4I0Fv2cydSPOtNL8hrk=; h=Date:From:To:Subject:In-Reply-To:From; b=IH66IRT6jYWxlBiclATZOqnq8lsijIlTTnZvYlrAu5xgHNch8DEzQdSUHWM5zg0FQ b/4L0kyh8He+zLZp5hUQwGmwknBW8mnDCsU4YmaEMIkMSKAjrmwNsT3Eylwah4OyYT v83F6RAQJcNlFa+ojfNaMm7JsCXmU2EWj4ygKM2o= Date: Fri, 04 Jun 2021 20:01:18 -0700 From: Andrew Morton To: akpm@linux-foundation.org, anshuman.khandual@arm.com, gerald.schaefer@linux.ibm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, stable@vger.kernel.org, torvalds@linux-foundation.org, vgupta@synopsys.com Subject: [patch 04/13] mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests() Message-ID: <20210605030118.fd0d-oaQo%akpm@linux-foundation.org> In-Reply-To: <20210604200040.d8d0406caf195525620c0f3d@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 From: Gerald Schaefer Subject: mm/debug_vm_pgtable: fix alignment for pmd/pud_advanced_tests() In pmd/pud_advanced_tests(), the vaddr is aligned up to the next pmd/pud entry, and so it does not match the given pmdp/pudp and (aligned down) pfn any more. For s390, this results in memory corruption, because the IDTE instruction used e.g. in xxx_get_and_clear() will take the vaddr for some calculations, in combination with the given pmdp. It will then end up with a wrong table origin, ending on ...ff8, and some of those wrongly set low-order bits will also select a wrong pagetable level for the index addition. IDTE could therefore invalidate (or 0x20) something outside of the page tables, depending on the wrongly picked index, which in turn depends on the random vaddr. As result, we sometimes see "BUG task_struct (Not tainted): Padding overwritten" on s390, where one 0x5a padding value got overwritten with 0x7a. Fix this by aligning down, similar to how the pmd/pud_aligned pfns are calculated. Link: https://lkml.kernel.org/r/20210525130043.186290-2-gerald.schaefer@linux.ibm.com Fixes: a5c3b9ffb0f40 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by: Gerald Schaefer Reviewed-by: Anshuman Khandual Cc: Vineet Gupta Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: [5.9+] Signed-off-by: Andrew Morton --- mm/debug_vm_pgtable.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-fix-alignment-for-pmd-pud_advanced_tests +++ a/mm/debug_vm_pgtable.c @@ -192,7 +192,7 @@ static void __init pmd_advanced_tests(st pr_debug("Validating PMD advanced\n"); /* Align the address wrt HPAGE_PMD_SIZE */ - vaddr = (vaddr & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE; + vaddr &= HPAGE_PMD_MASK; pgtable_trans_huge_deposit(mm, pmdp, pgtable); @@ -330,7 +330,7 @@ static void __init pud_advanced_tests(st pr_debug("Validating PUD advanced\n"); /* Align the address wrt HPAGE_PUD_SIZE */ - vaddr = (vaddr & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE; + vaddr &= HPAGE_PUD_MASK; set_pud_at(mm, vaddr, pudp, pud); pudp_set_wrprotect(mm, vaddr, pudp); _