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=-17.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D9D4FC07E95 for ; Sat, 3 Jul 2021 00:30:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 80BBB61427 for ; Sat, 3 Jul 2021 00:30:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 80BBB61427 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1A0D16B0011; Fri, 2 Jul 2021 20:30:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 151606B0036; Fri, 2 Jul 2021 20:30:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F0BC16B005D; Fri, 2 Jul 2021 20:30:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0046.hostedemail.com [216.40.44.46]) by kanga.kvack.org (Postfix) with ESMTP id C69F56B0011 for ; Fri, 2 Jul 2021 20:30:31 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 6B0D382499B9 for ; Sat, 3 Jul 2021 00:30:31 +0000 (UTC) X-FDA: 78319395462.10.B1F5BFD Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf04.hostedemail.com (Postfix) with ESMTP id EB2085000098 for ; Sat, 3 Jul 2021 00:30:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625272228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=triFGY+73M5BFO3B7XEpDoQJqmQeUSvePcDF+RZJGmw=; b=F2URWRtGaqS6vknCArynS9h1vizXpxnl3t4GYcAt0tqP+dzb91AKnJ9TXPlvJCT6jtdhTu AKSxGgeNtcUkRsFhPzQ8Zxn7v7Ep9rMdaCDCPl5tEcQcn4MTy5Ai8dWrPYs271DbGEgXTp 8jZiXq5tBin5NZQEEucTbQLzLRb81Cc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-132-ERmJkii2OZ6llbfVImClqA-1; Fri, 02 Jul 2021 20:30:25 -0400 X-MC-Unique: ERmJkii2OZ6llbfVImClqA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1867110C1ADC; Sat, 3 Jul 2021 00:30:24 +0000 (UTC) Received: from [10.64.54.119] (vpn2-54-119.bne.redhat.com [10.64.54.119]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A0E255D6D3; Sat, 3 Jul 2021 00:30:21 +0000 (UTC) Subject: Re: [PATCH] mm/debug_vm_pgtable: Fix corrupted PG_arch_1 by set_pmd_at() From: Gavin Shan To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, anshuman.khandual@arm.com, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, shan.gavin@gmail.com References: <20210702103225.51448-1-gshan@redhat.com> Message-ID: <0911a77c-efa6-99fe-ec1a-4b968ad925bf@redhat.com> Date: Sat, 3 Jul 2021 10:30:18 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20210702103225.51448-1-gshan@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=F2URWRtG; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf04.hostedemail.com: domain of gshan@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=gshan@redhat.com X-Stat-Signature: as55wpta9ug8f4wt78uig4oww3sjjhnj X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: EB2085000098 X-HE-Tag: 1625272230-638927 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 7/2/21 8:32 PM, Gavin Shan wrote: > There are two addresses selected: random virtual address and physical > address corresponding to kernel symbol @start_kernel. During the PMD > tests in pmd_advanced_tests(), the physical address is aligned down > to the starting address of the huge page, whose size is 512MB on ARM64 > when we have 64KB base page size. After that, set_pmd_at() is called > to populate the PMD entry. PG_arch_1, PG_dcache_clean on ARM64, is > set to the page flags. Unforunately, the page, corresponding to the > starting address of the huge page could be owned by buddy. It means > PG_arch_1 can be unconditionally set to page owned by buddy. > > Afterwards, the page with PG_arch_1 set is fetched from buddy's free > area list, but fails the checking. It leads to the following warning > on ARM64: > > BUG: Bad page state in process memhog pfn:08000 > page:0000000015c0a628 refcount:0 mapcount:0 \ > mapping:0000000000000000 index:0x1 pfn:0x8000 > flags: 0x7ffff8000000800(arch_1|node=0|zone=0|lastcpupid=0xfffff) > raw: 07ffff8000000800 dead000000000100 dead000000000122 0000000000000000 > raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 > page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag(s) set > > This fixes the issue by calling flush_dcache_page() after each call > to set_{pud, pmd, pte}_at() because PG_arch_1 isn't needed in any case. > > Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") > Cc: stable@vger.kernel.org # v5.9+ > Signed-off-by: Gavin Shan > --- > mm/debug_vm_pgtable.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 92bfc37300df..7dedf6c6dd25 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -29,6 +29,8 @@ > #include > #include > #include > + > +#include > #include > #include > > @@ -91,6 +93,7 @@ static void __init pte_advanced_tests(struct mm_struct *mm, > unsigned long pfn, unsigned long vaddr, > pgprot_t prot) > { > + struct page *page = pfn_to_page(pfn); > pte_t pte = pfn_pte(pfn, prot); > > /* > @@ -102,6 +105,7 @@ static void __init pte_advanced_tests(struct mm_struct *mm, > pr_debug("Validating PTE advanced\n"); > pte = pfn_pte(pfn, prot); > set_pte_at(mm, vaddr, ptep, pte); > + flush_dcache_page(page); > ptep_set_wrprotect(mm, vaddr, ptep); > pte = ptep_get(ptep); > WARN_ON(pte_write(pte)); > @@ -113,6 +117,7 @@ static void __init pte_advanced_tests(struct mm_struct *mm, > pte = pte_wrprotect(pte); > pte = pte_mkclean(pte); > set_pte_at(mm, vaddr, ptep, pte); > + flush_dcache_page(page); > pte = pte_mkwrite(pte); > pte = pte_mkdirty(pte); > ptep_set_access_flags(vma, vaddr, ptep, pte, 1); > @@ -125,6 +130,7 @@ static void __init pte_advanced_tests(struct mm_struct *mm, > pte = pfn_pte(pfn, prot); > pte = pte_mkyoung(pte); > set_pte_at(mm, vaddr, ptep, pte); > + flush_dcache_page(page); > ptep_test_and_clear_young(vma, vaddr, ptep); > pte = ptep_get(ptep); > WARN_ON(pte_young(pte)); > @@ -186,6 +192,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, > unsigned long pfn, unsigned long vaddr, > pgprot_t prot, pgtable_t pgtable) > { > + struct page *page = pfn_to_page(pfn); > pmd_t pmd; > > if (!has_transparent_hugepage()) > @@ -199,6 +206,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, > > pmd = pfn_pmd(pfn, prot); > set_pmd_at(mm, vaddr, pmdp, pmd); > + flush_dcache_page(page); > pmdp_set_wrprotect(mm, vaddr, pmdp); > pmd = READ_ONCE(*pmdp); > WARN_ON(pmd_write(pmd)); > @@ -210,6 +218,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, > pmd = pmd_wrprotect(pmd); > pmd = pmd_mkclean(pmd); > set_pmd_at(mm, vaddr, pmdp, pmd); > + flush_dcache_page(page); > pmd = pmd_mkwrite(pmd); > pmd = pmd_mkdirty(pmd); > pmdp_set_access_flags(vma, vaddr, pmdp, pmd, 1); > @@ -222,6 +231,7 @@ static void __init pmd_advanced_tests(struct mm_struct *mm, > pmd = pmd_mkhuge(pfn_pmd(pfn, prot)); > pmd = pmd_mkyoung(pmd); > set_pmd_at(mm, vaddr, pmdp, pmd); > + flush_dcache_page(page); > pmdp_test_and_clear_young(vma, vaddr, pmdp); > pmd = READ_ONCE(*pmdp); > WARN_ON(pmd_young(pmd)); > @@ -334,6 +344,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm, > unsigned long pfn, unsigned long vaddr, > pgprot_t prot) > { > + struct page *page = pfn_to_page(page); > pud_t pud; > Typo here. @page should be replaced by @pfn. I'm holding to post v2 until I receive comments on v1. > if (!has_transparent_hugepage()) > @@ -345,6 +356,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm, > > pud = pfn_pud(pfn, prot); > set_pud_at(mm, vaddr, pudp, pud); > + flush_dcache_page(page); > pudp_set_wrprotect(mm, vaddr, pudp); > pud = READ_ONCE(*pudp); > WARN_ON(pud_write(pud)); > @@ -358,6 +370,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm, > pud = pud_wrprotect(pud); > pud = pud_mkclean(pud); > set_pud_at(mm, vaddr, pudp, pud); > + flush_dcache_page(page); > pud = pud_mkwrite(pud); > pud = pud_mkdirty(pud); > pudp_set_access_flags(vma, vaddr, pudp, pud, 1); > @@ -373,6 +386,7 @@ static void __init pud_advanced_tests(struct mm_struct *mm, > pud = pfn_pud(pfn, prot); > pud = pud_mkyoung(pud); > set_pud_at(mm, vaddr, pudp, pud); > + flush_dcache_page(page); > pudp_test_and_clear_young(vma, vaddr, pudp); > pud = READ_ONCE(*pudp); > WARN_ON(pud_young(pud)); > @@ -604,6 +618,7 @@ static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep, > unsigned long pfn, unsigned long vaddr, > pgprot_t prot) > { > + struct page *page = pfn_to_page(pfn); > pte_t pte = pfn_pte(pfn, prot); > > pr_debug("Validating PTE clear\n"); > @@ -611,6 +626,7 @@ static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep, > pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > #endif > set_pte_at(mm, vaddr, ptep, pte); > + flush_dcache_page(page); > barrier(); > pte_clear(mm, vaddr, ptep); > pte = ptep_get(ptep); > Thanks, Gavin