From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751948AbeA0Hz2 (ORCPT ); Sat, 27 Jan 2018 02:55:28 -0500 Received: from mx2.suse.de ([195.135.220.15]:54253 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751267AbeA0HzZ (ORCPT ); Sat, 27 Jan 2018 02:55:25 -0500 Date: Fri, 26 Jan 2018 15:04:15 +0100 From: Michal Hocko To: Anshuman Khandual Cc: Michael Ellerman , akpm@linux-foundation.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-next@vger.kernel.org, sfr@canb.auug.org.au, broonie@kernel.org Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE Message-ID: <20180126140415.GD5027@dhcp22.suse.cz> References: <20180109161355.GL1732@dhcp22.suse.cz> <20180117080731.GA2900@dhcp22.suse.cz> <082aa008-c56a-681d-0949-107245603a97@linux.vnet.ibm.com> <20180123124545.GL1526@dhcp22.suse.cz> <20180123160653.GU1526@dhcp22.suse.cz> <2a05eaf2-20fd-57a8-d4bd-5a1fbf57686c@linux.vnet.ibm.com> <20180124090539.GH1526@dhcp22.suse.cz> <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 26-01-18 18:04:27, Anshuman Khandual wrote: [...] > I tried to instrument mmap_region() for a single instance of 'sed' > binary and traced all it's VMA creation. But there is no trace when > that 'anon' VMA got created which suddenly shows up during subsequent > elf_map() call eventually failing it. Please note that the following > VMA was never created through call into map_region() in the process > which is strange. Could you share your debugging patch? > ================================================================= > [ 9.076867] Details for VMA[3] c000001fce42b7c0 > [ 9.076925] vma c000001fce42b7c0 start 0000000010030000 end 0000000010040000 > next c000001fce42b580 prev c000001fce42b880 mm c000001fce40fa00 > prot 8000000000000104 anon_vma (null) vm_ops (null) > pgoff 1003 file (null) private_data (null) > flags: 0x100073(read|write|mayread|maywrite|mayexec|account) > ================================================================= Isn't this vdso or some other special mapping? It is not really an anonymous vma. Please hook into __install_special_mapping > VMA creation for 'sed' binary > ============================= > [ 9.071902] XXX: mm c000001fce40fa00 registered > > [ 9.071971] Total VMAs 2 on MM c000001fce40fa00 > ---- > [ 9.072010] Details for VMA[1] c000001fce42bdc0 > [ 9.072064] vma c000001fce42bdc0 start 0000000010000000 end 0000000010020000 > next c000001fce42b580 prev (null) mm c000001fce40fa00 > prot 8000000000000105 anon_vma (null) vm_ops c008000011ddca18 > pgoff 0 file c000001fe2969a00 private_data (null) > flags: 0x875(read|exec|mayread|maywrite|mayexec|denywrite) This one doesn't have any stack trace either... Yet it is a file mapping obviously. Special mappings shouldn't have any file associated. Strange... -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 26 Jan 2018 15:04:15 +0100 From: Michal Hocko To: Anshuman Khandual Cc: Michael Ellerman , akpm@linux-foundation.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-next@vger.kernel.org, sfr@canb.auug.org.au, broonie@kernel.org Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE Message-ID: <20180126140415.GD5027@dhcp22.suse.cz> References: <20180109161355.GL1732@dhcp22.suse.cz> <20180117080731.GA2900@dhcp22.suse.cz> <082aa008-c56a-681d-0949-107245603a97@linux.vnet.ibm.com> <20180123124545.GL1526@dhcp22.suse.cz> <20180123160653.GU1526@dhcp22.suse.cz> <2a05eaf2-20fd-57a8-d4bd-5a1fbf57686c@linux.vnet.ibm.com> <20180124090539.GH1526@dhcp22.suse.cz> <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: On Fri 26-01-18 18:04:27, Anshuman Khandual wrote: [...] > I tried to instrument mmap_region() for a single instance of 'sed' > binary and traced all it's VMA creation. But there is no trace when > that 'anon' VMA got created which suddenly shows up during subsequent > elf_map() call eventually failing it. Please note that the following > VMA was never created through call into map_region() in the process > which is strange. Could you share your debugging patch? > ================================================================= > [ 9.076867] Details for VMA[3] c000001fce42b7c0 > [ 9.076925] vma c000001fce42b7c0 start 0000000010030000 end 0000000010040000 > next c000001fce42b580 prev c000001fce42b880 mm c000001fce40fa00 > prot 8000000000000104 anon_vma (null) vm_ops (null) > pgoff 1003 file (null) private_data (null) > flags: 0x100073(read|write|mayread|maywrite|mayexec|account) > ================================================================= Isn't this vdso or some other special mapping? It is not really an anonymous vma. Please hook into __install_special_mapping > VMA creation for 'sed' binary > ============================= > [ 9.071902] XXX: mm c000001fce40fa00 registered > > [ 9.071971] Total VMAs 2 on MM c000001fce40fa00 > ---- > [ 9.072010] Details for VMA[1] c000001fce42bdc0 > [ 9.072064] vma c000001fce42bdc0 start 0000000010000000 end 0000000010020000 > next c000001fce42b580 prev (null) mm c000001fce40fa00 > prot 8000000000000105 anon_vma (null) vm_ops c008000011ddca18 > pgoff 0 file c000001fe2969a00 private_data (null) > flags: 0x875(read|exec|mayread|maywrite|mayexec|denywrite) This one doesn't have any stack trace either... Yet it is a file mapping obviously. Special mappings shouldn't have any file associated. Strange... -- Michal Hocko SUSE Labs -- 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