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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9167C4332F for ; Mon, 6 Nov 2023 03:09:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 337AD8D0008; Sun, 5 Nov 2023 22:09:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2E7D08D0002; Sun, 5 Nov 2023 22:09:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1D68C8D0008; Sun, 5 Nov 2023 22:09:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 0E4078D0002 for ; Sun, 5 Nov 2023 22:09:36 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D6CF6C062E for ; Mon, 6 Nov 2023 03:09:35 +0000 (UTC) X-FDA: 81426049110.05.CB66401 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf30.hostedemail.com (Postfix) with ESMTP id BC8C580008 for ; Mon, 6 Nov 2023 03:09:33 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1699240174; a=rsa-sha256; cv=none; b=fNxlfNqF2+I4bYVcbST2St5foNTTcq9ccu8OP5S90S0WgcxZlqf3yrxF1e+ml17CatGbU/ eqF7DeTwB8fq+ufORrIQ2cHikgPCawRW7rDdfbeO1ffy5xTBfysyFXFAj4Dbb1z+oTLNJ+ RXR+iaKeepruZHcfVLNuRy4jHeJ6BvY= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=none; spf=pass (imf30.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1699240174; h=from:from:sender: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=k0hq+1F6StUHnbk9VYw5o80b8p4SuFq192Bpgm2Y4Fc=; b=tmS6Dc/RF6/4cSjMMw2ebr0oCoZXpK5EFIEUtipbrivHlSUTyt6PakPwuLjHqZ2emh4KE8 qu51W75VJ1I3Z2wAxTDKDGpVQ9mkUwkBblAFQCrEw89s9DBkBgOVBpYytBwU5z4XA7Rgs5 kHhUif7M8wa8l6LxWQQeTRSaR65HyTQ= 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 791E3C15; Sun, 5 Nov 2023 19:10:16 -0800 (PST) Received: from [10.162.41.8] (a077893.blr.arm.com [10.162.41.8]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E226E3F64C; Sun, 5 Nov 2023 19:09:29 -0800 (PST) Message-ID: Date: Mon, 6 Nov 2023 08:39:26 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: mm/debug_vm_pgtable.c:860 warning triggered To: "Daniel Walker (danielwa)" , Christophe Leroy , "Aneesh Kumar K . V" , Michael Ellerman Cc: "David Beazley (dbeazley)" , "xe-linux-external(mailer list)" , "linux-mm@kvack.org" , "linuxppc-dev@lists.ozlabs.org" References: Content-Language: en-US From: Anshuman Khandual In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: BC8C580008 X-Stat-Signature: p549hpteaq7zr5mtjdmu1cxhcibkcn1s X-HE-Tag: 1699240173-255573 X-HE-Meta: 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 fpe3nsbl aE19pxO1nTnNDKCt+jAx/36jM4FTFNuCOF7UmjDcGd32SyTFl5ht19CzzcTReyrJtzArk7PeOzjWOpFHYKzg5vcYz3QUI8zNAX0CWjkr8Y3B1nQh+RXkzXNILO1xZcIB8H/oMwfkqyXE76Da0KJcncrKBov9hbn03b/F9KInrrg2VpES3taUY/VVitvErN0dGYANXdqVmOPnoZKQtO8ct26jy8iyUkVJa6j0ajm8wBmgBKY0= 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: List-Subscribe: List-Unsubscribe: Hello Daniel, This test just ensures that PFN is preserved during pte <--> swap pte transformations , and the warning here seems to have been caused by powerpc platform specific helpers and/or its pte_t representation. Adding powerpc folks and platform mailing list here. - Anshuman On 11/4/23 04:42, Daniel Walker (danielwa) wrote: > > Hi, > > This warning has triggered on our powerpc equipment. > > debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page table helpers > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 1 at mm/debug_vm_pgtable.c:860 0xc1012190 > Modules linked in: > CPU: 0 PID: 1 Comm: swapper Not tainted 6.6.0 #14 > Hardware name: MPC8544DS e500v2 0x80210030 MPC8544 DS > NIP: c1012190 LR: c101216c CTR: 00000000 > REGS: c145bc70 TRAP: 0700 Not tainted (6.6.0) > MSR: 00029000 CR: 48000248 XER: 00000000 > > GPR00: c1012094 c145bd60 c1498000 c145bd6c 0000003c 00000000 7cffffff 00000001 > GPR08: efa2d000 00000000 00000000 2d589a6c 88000248 00000000 c000343c 00000000 > GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c10000d8 > GPR24: 00000000 00000000 00000000 00000000 00000000 00000200 fffffffc 7cffffff > Call Trace: > [c145bd60] [c1012094] 0xc1012094 (unreliable) > [c145be30] [c0003044] 0xc0003044 > [c145bea0] [c1000ea0] 0xc1000ea0 > [c145bee0] [c0003460] 0xc0003460 > [c145bf00] [c0011224] 0xc0011224 > --- interrupt: 0 at 0x00000000 > NIP: 00000000 LR: 00000000 CTR: 00000000 > REGS: c145bf10 TRAP: 0000 Not tainted (6.6.0) > MSR: 00000000 <> CR: 00000000 XER: 00000000 > > GPR00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > GPR08: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > --- interrupt: 0 > Code: 3861000c 38a00000 4b10a235 8121000c 7c1f4800 41820008 0fe00000 8121006c 7d29e378 5529463e 7c1d4840 41820008 <0fe00000> 81410080 2c0affff 41820058 > ---[ end trace 0000000000000000 ]--- > > This appears to be the following code, > > 850 > 851 static void __init pte_swap_tests(struct pgtable_debug_args *args) > 852 { > 853 swp_entry_t swp; > 854 pte_t pte; > 855 > 856 pr_debug("Validating PTE swap\n"); > 857 pte = pfn_pte(args->fixed_pte_pfn, args->page_prot); > 858 swp = __pte_to_swp_entry(pte); > 859 pte = __swp_entry_to_pte(swp); > 860 WARN_ON(args->fixed_pte_pfn != pte_pfn(pte)); > 861 } > 862 > > > This only happens in powerpc with the following config options enabled, > > CONFIG_PTE_64BIT=y > CONFIG_PHYS_64BIT=y > > These options can increase the pte_t type to 64bits, which swp_entry_t remains unsigned > long which is 32 bits on there systems. This warning appears to have triggered since the > inclusion of CONFIG_DEBUG_VM_PGTABLE support for powerpc. > > To reproduce the issue you can use the attached config to build a powerpc kernel. Then > boot with QEMU using the following command line. > > qemu-system-ppc -M mpc8544ds -kernel ../powerpc/vmlinux -append "console=ttyS0" -nographic > > Please CC me on any fixes in the future. > > Thanks, > > Daniel >