From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752130AbeAWQG7 (ORCPT ); Tue, 23 Jan 2018 11:06:59 -0500 Received: from mx2.suse.de ([195.135.220.15]:58996 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751318AbeAWQG5 (ORCPT ); Tue, 23 Jan 2018 11:06:57 -0500 Date: Tue, 23 Jan 2018 17:06:53 +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: <20180123160653.GU1526@dhcp22.suse.cz> References: <87mv1phptq.fsf@concordia.ellerman.id.au> <7a44f42e-39d0-1c4b-19e0-7df1b0842c18@linux.vnet.ibm.com> <87tvvw80f2.fsf@concordia.ellerman.id.au> <96458c0a-e273-3fb9-a33b-f6f2d536f90b@linux.vnet.ibm.com> <20180109161355.GL1732@dhcp22.suse.cz> <20180117080731.GA2900@dhcp22.suse.cz> <082aa008-c56a-681d-0949-107245603a97@linux.vnet.ibm.com> <20180123124545.GL1526@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Tue 23-01-18 21:28:28, Anshuman Khandual wrote: > On 01/23/2018 06:15 PM, Michal Hocko wrote: > > On Tue 23-01-18 16:55:18, Anshuman Khandual wrote: > >> On 01/17/2018 01:37 PM, Michal Hocko wrote: > >>> On Thu 11-01-18 15:38:37, Anshuman Khandual wrote: > >>>> On 01/09/2018 09:43 PM, Michal Hocko wrote: > >>> [...] > >>>>> Did you manage to catch _who_ is requesting that anonymous mapping? Do > >>>>> you need a help with the debugging patch? > >>>> > >>>> Not yet, will get back on this. > >>> > >>> ping? > >> > >> Hey Michal, > >> > >> Missed this thread, my apologies. This problem is happening only with > >> certain binaries like 'sed', 'tmux', 'hostname', 'pkg-config' etc. As > >> you had mentioned before the map request collision is happening on > >> [10030000, 10040000] and [10030000, 10040000] ranges only which is > >> just a single PAGE_SIZE. You asked previously that who might have > >> requested the anon mapping which is already present in there ? Would > >> not that be the same process itself ? I am bit confused. > > > > We are early in the ELF loading. If we are mapping over an existing > > mapping then we are effectivelly corrupting it. In other words exactly > > what this patch tries to prevent. I fail to see what would be a relevant > > anon mapping this early and why it would be colliding with elf > > segements. > > > >> Would it be > >> helpful to trap all the mmap() requests from any of the binaries > >> and see where we might have created that anon mapping ? > > > > Yeah, that is exactly what I was suggesting. Sorry for not being clear > > about that. > > > > Tried to instrument just for the 'sed' binary and dont see any where > it actually requests the anon VMA which got hit when loading the ELF > section which is strange. All these requested flags here already has > MAP_FIXED_NOREPLACE (0x100000). Wondering from where the anon VMA > actually came from. Could you try to dump backtrace? -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 23 Jan 2018 17:06:53 +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: <20180123160653.GU1526@dhcp22.suse.cz> References: <87mv1phptq.fsf@concordia.ellerman.id.au> <7a44f42e-39d0-1c4b-19e0-7df1b0842c18@linux.vnet.ibm.com> <87tvvw80f2.fsf@concordia.ellerman.id.au> <96458c0a-e273-3fb9-a33b-f6f2d536f90b@linux.vnet.ibm.com> <20180109161355.GL1732@dhcp22.suse.cz> <20180117080731.GA2900@dhcp22.suse.cz> <082aa008-c56a-681d-0949-107245603a97@linux.vnet.ibm.com> <20180123124545.GL1526@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: On Tue 23-01-18 21:28:28, Anshuman Khandual wrote: > On 01/23/2018 06:15 PM, Michal Hocko wrote: > > On Tue 23-01-18 16:55:18, Anshuman Khandual wrote: > >> On 01/17/2018 01:37 PM, Michal Hocko wrote: > >>> On Thu 11-01-18 15:38:37, Anshuman Khandual wrote: > >>>> On 01/09/2018 09:43 PM, Michal Hocko wrote: > >>> [...] > >>>>> Did you manage to catch _who_ is requesting that anonymous mapping? Do > >>>>> you need a help with the debugging patch? > >>>> > >>>> Not yet, will get back on this. > >>> > >>> ping? > >> > >> Hey Michal, > >> > >> Missed this thread, my apologies. This problem is happening only with > >> certain binaries like 'sed', 'tmux', 'hostname', 'pkg-config' etc. As > >> you had mentioned before the map request collision is happening on > >> [10030000, 10040000] and [10030000, 10040000] ranges only which is > >> just a single PAGE_SIZE. You asked previously that who might have > >> requested the anon mapping which is already present in there ? Would > >> not that be the same process itself ? I am bit confused. > > > > We are early in the ELF loading. If we are mapping over an existing > > mapping then we are effectivelly corrupting it. In other words exactly > > what this patch tries to prevent. I fail to see what would be a relevant > > anon mapping this early and why it would be colliding with elf > > segements. > > > >> Would it be > >> helpful to trap all the mmap() requests from any of the binaries > >> and see where we might have created that anon mapping ? > > > > Yeah, that is exactly what I was suggesting. Sorry for not being clear > > about that. > > > > Tried to instrument just for the 'sed' binary and dont see any where > it actually requests the anon VMA which got hit when loading the ELF > section which is strange. All these requested flags here already has > MAP_FIXED_NOREPLACE (0x100000). Wondering from where the anon VMA > actually came from. Could you try to dump backtrace? -- 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