From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753319AbeDSSxz (ORCPT ); Thu, 19 Apr 2018 14:53:55 -0400 Received: from mga02.intel.com ([134.134.136.20]:62138 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753057AbeDSSxx (ORCPT ); Thu, 19 Apr 2018 14:53:53 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,297,1520924400"; d="scan'208";a="35565935" Subject: Re: BUG: Bad page map in process python2 pte:10000000000 pmd:17e8be067 To: Fengguang Wu , linux-mm@kvack.org References: <20180419054047.xxiljmzaf2u7odc6@wfg-t540p.sh.intel.com> Cc: Andrew Morton , Michal Hocko , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Mel Gorman , Huang Ying , Ross Zwisler , Minchan Kim , Hugh Dickins , linux-kernel@vger.kernel.org, lkp@01.org From: Dave Hansen Message-ID: <17463682-dc08-358d-8b44-02821352604c@intel.com> Date: Thu, 19 Apr 2018 11:53:51 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180419054047.xxiljmzaf2u7odc6@wfg-t540p.sh.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/18/2018 10:40 PM, Fengguang Wu wrote: > [ 716.494065] PASS concurrent_autogo_5ghz_ht40 4.803608 2018-03-23 09:57:21.586794 > [ 716.494069] > [ 716.496923] passed all 1 test case(s) > [ 716.496926] > [ 716.511702] swap_info_get: Bad swap file entry 04000000 > [ 716.512731] BUG: Bad page map in process python2 pte:100_0000_0000 pmd:17e8be067 > [ 716.513844] addr:00000000860ba23b vm_flags:00000070 anon_vma: (null) mapping:000000004c76fece index:1e2 > [ 716.515160] file:libpcre.so.3.13.3 fault:filemap_fault mmap:generic_file_mmap readpage:simple_readpage > [ 716.516418] CPU: 2 PID: 8907 Comm: python2 Not tainted 4.16.0-rc5 #1 > [ 716.517533] Hardware name: /DH67GD, BIOS BLH6710H.86A.0132.2011.1007.1505 10/07/2011 Did you say that you have a few more examples of this? I would be really interested if it's always python or always the same shared library, or always file-backed memory, always the same bit, etc... From the vm_flags, I'd guess that this is the "rw-p" part of the file mapping. The bit that gets set is really weird. It's bit 40. I could definitely see scenarios where we might set the dirty bit, or even NX for that matter, or some *bit* that we mess with in software. It's not even close to the boundary where it could represent a swapoffset=1 or swapfile=1. It's also unlikely to be _PAGE_PSE having gone missing from the PMD since it's in the middle of a file-backed mapping and the PMD is obviously pointing to a 4k page. If I had to put money on it, I'd guess it's a hardware bit flip, or less likely, a rogue software bit flip. But, more examples will hopefully shed some more light. From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============7967251221074137557==" MIME-Version: 1.0 From: Dave Hansen To: lkp@lists.01.org Subject: Re: BUG: Bad page map in process python2 pte:10000000000 pmd:17e8be067 Date: Thu, 19 Apr 2018 11:53:51 -0700 Message-ID: <17463682-dc08-358d-8b44-02821352604c@intel.com> In-Reply-To: <20180419054047.xxiljmzaf2u7odc6@wfg-t540p.sh.intel.com> List-Id: --===============7967251221074137557== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 04/18/2018 10:40 PM, Fengguang Wu wrote: > [ 716.494065] PASS concurrent_autogo_5ghz_ht40 4.803608 2018-03-23 09:57= :21.586794 > [ 716.494069] > [ 716.496923] passed all 1 test case(s) > [ 716.496926] > [ 716.511702] swap_info_get: Bad swap file entry 04000000 > [ 716.512731] BUG: Bad page map in process python2 pte:100_0000_0000 pm= d:17e8be067 > [ 716.513844] addr:00000000860ba23b vm_flags:00000070 anon_vma: = (null) mapping:000000004c76fece index:1e2 > [ 716.515160] file:libpcre.so.3.13.3 fault:filemap_fault mmap:generic_fi= le_mmap readpage:simple_readpage > [ 716.516418] CPU: 2 PID: 8907 Comm: python2 Not tainted 4.16.0-rc5 #1 > [ 716.517533] Hardware name: /DH67GD, BIOS BLH6710H.86A.0132.2011.1007.= 1505 10/07/2011 Did you say that you have a few more examples of this? I would be really interested if it's always python or always the same shared library, or always file-backed memory, always the same bit, etc... From the vm_flags, I'd guess that this is the "rw-p" part of the file mapping. The bit that gets set is really weird. It's bit 40. I could definitely see scenarios where we might set the dirty bit, or even NX for that matter, or some *bit* that we mess with in software. It's not even close to the boundary where it could represent a swapoffset=3D1 or swapfile= =3D1. It's also unlikely to be _PAGE_PSE having gone missing from the PMD since it's in the middle of a file-backed mapping and the PMD is obviously pointing to a 4k page. If I had to put money on it, I'd guess it's a hardware bit flip, or less likely, a rogue software bit flip. But, more examples will hopefully shed some more light. --===============7967251221074137557==--