From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id EA74D6B02F2 for ; Tue, 2 May 2017 04:54:48 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id t7so55261272pgt.6 for ; Tue, 02 May 2017 01:54:48 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [45.249.212.188]) by mx.google.com with ESMTPS id j88si16971007pfj.117.2017.05.02.01.54.47 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 02 May 2017 01:54:48 -0700 (PDT) Message-ID: <590848B0.2000801@huawei.com> Date: Tue, 2 May 2017 16:52:00 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [RFC] dev/mem: "memtester -p 0x6c80000000000 10G" cause crash References: <59083C5B.5080204@huawei.com> <20170502084323.GG14593@dhcp22.suse.cz> In-Reply-To: <20170502084323.GG14593@dhcp22.suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Mel Gorman , Vlastimil Babka , Joonsoo Kim , Johannes Weiner , Rik van Riel , Shakeel Butt , Linux MM , LKML , zhong jiang On 2017/5/2 16:43, Michal Hocko wrote: > On Tue 02-05-17 15:59:23, Xishi Qiu wrote: >> Hi, I use "memtester -p 0x6c80000000000 10G" to test physical address 0x6c80000000000 >> Because this physical address is invalid, and valid_mmap_phys_addr_range() >> always return 1, so it causes crash. >> >> My question is that should the user assure the physical address is valid? > > We already seem to be checking range_is_allowed(). What is your > CONFIG_STRICT_DEVMEM setting? The code seems to be rather confusing but > my assumption is that you better know what you are doing when mapping > this file. > HI Michal, CONFIG_STRICT_DEVMEM=y, and range_is_allowed() will skip memory, but 0x6c80000000000 is not memory, it is just a invalid address, so it cause crash. You mean the user should assure the physical address is valid, right? Thanks, Xishi Qiu >> ... >> [ 169.147578] ? panic+0x1f1/0x239 >> [ 169.150789] oops_end+0xb8/0xd0 >> [ 169.153910] pgtable_bad+0x8a/0x95 >> [ 169.157294] __do_page_fault+0x3aa/0x4a0 >> [ 169.161194] do_page_fault+0x30/0x80 >> [ 169.164750] ? do_syscall_64+0x175/0x180 >> [ 169.168649] page_fault+0x28/0x30 >> >> Thanks, >> Xishi Qiu > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org