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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 3B9F8C3A59F for ; Sun, 18 Aug 2019 08:20:49 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EA4CA21773 for ; Sun, 18 Aug 2019 08:20:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA4CA21773 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6FD3A6B000C; Sun, 18 Aug 2019 04:20:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6ADCC6B000D; Sun, 18 Aug 2019 04:20:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C4E96B000E; Sun, 18 Aug 2019 04:20:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0158.hostedemail.com [216.40.44.158]) by kanga.kvack.org (Postfix) with ESMTP id 3CA4E6B000C for ; Sun, 18 Aug 2019 04:20:48 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id E07D48248AC2 for ; Sun, 18 Aug 2019 08:20:47 +0000 (UTC) X-FDA: 75834852534.04.vase86_411ab8ae28508 X-HE-Tag: vase86_411ab8ae28508 X-Filterd-Recvd-Size: 6846 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Sun, 18 Aug 2019 08:20:47 +0000 (UTC) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x7I8GVv5130383 for ; Sun, 18 Aug 2019 04:20:45 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2uey3v64dj-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 18 Aug 2019 04:20:45 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Sun, 18 Aug 2019 09:20:39 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7I8KcEF37879812 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 18 Aug 2019 08:20:38 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B902DA404D; Sun, 18 Aug 2019 08:20:38 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A7FDAA4059; Sun, 18 Aug 2019 08:20:37 +0000 (GMT) Received: from rapoport-lnx (unknown [9.148.8.59]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Sun, 18 Aug 2019 08:20:37 +0000 (GMT) Date: Sun, 18 Aug 2019 11:20:35 +0300 From: Mike Rapoport To: Zhaoyang Huang Cc: Russell King - ARM Linux admin , Andrew Morton , Zhaoyang Huang , Rob Herring , Florian Fainelli , Geert Uytterhoeven , Doug Berger , "open list:MEMORY MANAGEMENT" , LKML Subject: Re: [PATCH] arch : arm : add a criteria for pfn_valid References: <1566010813-27219-1-git-send-email-huangzhaoyang@gmail.com> <20190817183240.GM13294@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 19081808-0020-0000-0000-00000360F422 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19081808-0021-0000-0000-000021B61BE5 Message-Id: <20190818082035.GD10627@rapoport-lnx> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-18_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908180092 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 Sun, Aug 18, 2019 at 03:46:51PM +0800, Zhaoyang Huang wrote: > On Sun, Aug 18, 2019 at 2:32 AM Russell King - ARM Linux admin > wrote: > > > > On Sat, Aug 17, 2019 at 11:00:13AM +0800, Zhaoyang Huang wrote: > > > From: Zhaoyang Huang > > > > > > pfn_valid can be wrong while the MSB of physical address be trimed as pfn > > > larger than the max_pfn. > > > > What scenario are you addressing here? At a guess, you're addressing > > the non-LPAE case with PFNs that correspond with >= 4GiB of memory? > Please find bellowing for the callstack caused by this defect. The > original reason is a invalid PFN passed from userspace which will > introduce a invalid page within stable_page_flags and then kernel > panic. Yeah, arm64 hit this issue a while ago and it was fixed with commit 5ad356eabc47 ("arm64: mm: check for upper PAGE_SHIFT bits in pfn_valid()"). IMHO, the check if ((addr >> PAGE_SHIFT) != pfn) is more robust than comparing pfn to max_pfn. > [46886.723249] c7 [] (stable_page_flags) from [] > (kpageflags_read+0x90/0x11c) > [46886.723256] c7 r9:c101ce04 r8:c2d0bf70 r7:c2d0bf70 r6:1fbb10fb > r5:a8686f08 r4:a8686f08 > [46886.723264] c7 [] (kpageflags_read) from [] > (proc_reg_read+0x80/0x94) > [46886.723270] c7 r10:000000b4 r9:00000008 r8:c2d0bf70 r7:00000000 > r6:00000001 r5:ed8e7240 > [46886.723272] c7 r4:00000000 > [46886.723280] c7 [] (proc_reg_read) from [] > (__vfs_read+0x48/0x150) > [46886.723284] c7 r7:c2d0bf70 r6:c0f09208 r5:c0a4f940 r4:c40326c0 > [46886.723290] c7 [] (__vfs_read) from [] > (vfs_read+0xa4/0x158) > [46886.723296] c7 r9:a8686f08 r8:00000008 r7:c2d0bf70 r6:a8686f08 > r5:c40326c0 r4:00000008 > [46886.723301] c7 [] (vfs_read) from [] > (SyS_pread64+0x80/0xb8) > [46886.723306] c7 r8:00000008 r7:c0f09208 r6:c40326c0 r5:c40326c0 r4:fdd887d8 > [46886.723315] c7 [] (SyS_pread64) from [] > (ret_fast_syscall+0x0/0x28) > > > > > > > > > Signed-off-by: Zhaoyang Huang > > > --- > > > arch/arm/mm/init.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c > > > index c2daabb..9c4d938 100644 > > > --- a/arch/arm/mm/init.c > > > +++ b/arch/arm/mm/init.c > > > @@ -177,7 +177,8 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max_low, > > > #ifdef CONFIG_HAVE_ARCH_PFN_VALID > > > int pfn_valid(unsigned long pfn) > > > { > > > - return memblock_is_map_memory(__pfn_to_phys(pfn)); > > > + return (pfn > max_pfn) ? > > > + false : memblock_is_map_memory(__pfn_to_phys(pfn)); > > > } > > > EXPORT_SYMBOL(pfn_valid); > > > #endif > > > -- > > > 1.9.1 > > > > > > > > > > -- > > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > > According to speedtest.net: 11.9Mbps down 500kbps up > -- Sincerely yours, Mike.