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=-13.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 59257C433E6 for ; Tue, 1 Sep 2020 03:26:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1B5B220719 for ; Tue, 1 Sep 2020 03:26:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B5B220719 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AB3356B0003; Mon, 31 Aug 2020 23:26:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A67106B0037; Mon, 31 Aug 2020 23:26:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 979966B0055; Mon, 31 Aug 2020 23:26:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0207.hostedemail.com [216.40.44.207]) by kanga.kvack.org (Postfix) with ESMTP id 830416B0003 for ; Mon, 31 Aug 2020 23:26:35 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 446241EE6 for ; Tue, 1 Sep 2020 03:26:35 +0000 (UTC) X-FDA: 77213055150.06.worm80_480f90527095 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 0DDE81003D976 for ; Tue, 1 Sep 2020 03:26:35 +0000 (UTC) X-HE-Tag: worm80_480f90527095 X-Filterd-Recvd-Size: 4471 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 1 Sep 2020 03:26:34 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1826030E; Mon, 31 Aug 2020 20:26:34 -0700 (PDT) Received: from [192.168.0.130] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 352D43F68F; Mon, 31 Aug 2020 20:26:28 -0700 (PDT) From: Anshuman Khandual Subject: Re: [PATCH v3 13/13] mm/debug_vm_pgtable: populate a pte entry before fetching it To: "Aneesh Kumar K.V" , linux-mm@kvack.org, akpm@linux-foundation.org Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-snps-arc@lists.infradead.org, x86@kernel.org, linux-arch@vger.kernel.org, Gerald Schaefer , Christophe Leroy , Vineet Gupta , Mike Rapoport , Qian Cai References: <20200827080438.315345-1-aneesh.kumar@linux.ibm.com> <20200827080438.315345-14-aneesh.kumar@linux.ibm.com> Message-ID: Date: Tue, 1 Sep 2020 08:55:56 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200827080438.315345-14-aneesh.kumar@linux.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 0DDE81003D976 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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 08/27/2020 01:34 PM, Aneesh Kumar K.V wrote: > pte_clear_tests operate on an existing pte entry. Make sure that is not a none > pte entry. > > Signed-off-by: Aneesh Kumar K.V > --- > mm/debug_vm_pgtable.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index 21329c7d672f..8527ebb75f2c 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -546,7 +546,7 @@ static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep, > unsigned long vaddr) > { > - pte_t pte = ptep_get(ptep); > + pte_t pte = ptep_get_and_clear(mm, vaddr, ptep); Seems like ptep_get_and_clear() here just clears the entry in preparation for a following set_pte_at() which otherwise would have been a problem on ppc64 as you had pointed out earlier i.e set_pte_at() should not update an existing valid entry. So the commit message here is bit misleading. > > pr_debug("Validating PTE clear\n"); > pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > @@ -944,7 +944,7 @@ static int __init debug_vm_pgtable(void) > p4d_t *p4dp, *saved_p4dp; > pud_t *pudp, *saved_pudp; > pmd_t *pmdp, *saved_pmdp, pmd; > - pte_t *ptep; > + pte_t *ptep, pte; > pgtable_t saved_ptep; > pgprot_t prot, protnone; > phys_addr_t paddr; > @@ -1049,6 +1049,8 @@ static int __init debug_vm_pgtable(void) > */ > > ptep = pte_alloc_map_lock(mm, pmdp, vaddr, &ptl); > + pte = pfn_pte(pte_aligned, prot); > + set_pte_at(mm, vaddr, ptep, pte); Not here, creating and populating an entry must be done in respective test functions itself. Besides, this seems bit redundant as well. The test pte_clear_tests() with the above change added, already - Clears the PTEP entry with ptep_get_and_clear() - Creates and populates the PTEP with set_pte_at() - Clears with pte_clear() - Checks for pte_none() If the objective is to clear the PTEP entry before calling set_pte_at(), then only the first chunk is required and it should also be merged with a previous patch. [PATCH v3 07/13] mm/debug_vm_pgtable/set_pte/pmd/pud: Don't use set_*_at to update an existing pte entry > pte_clear_tests(mm, ptep, vaddr); > pte_advanced_tests(mm, vma, ptep, pte_aligned, vaddr, prot); > pte_unmap_unlock(ptep, ptl); > There is a checkpatch.pl warning here. WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line) #7: pte_clear_tests operate on an existing pte entry. Make sure that is not a none total: 0 errors, 1 warnings, 24 lines checked There is also a build failure on x86 reported from kernel test robot.