From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934693AbeBMKAZ (ORCPT ); Tue, 13 Feb 2018 05:00:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:55363 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933416AbeBMKAT (ORCPT ); Tue, 13 Feb 2018 05:00:19 -0500 Date: Tue, 13 Feb 2018 11:00:16 +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: <20180213100016.GL3443@dhcp22.suse.cz> References: <15da8c87-e6db-13aa-01c8-a913656bfdb6@linux.vnet.ibm.com> <6db9b33d-fd46-c529-b357-3397926f0733@linux.vnet.ibm.com> <20180129132235.GE21609@dhcp22.suse.cz> <87k1w081e7.fsf@concordia.ellerman.id.au> <20180130094205.GS21609@dhcp22.suse.cz> <5eccdc1b-6a10-b48a-c63f-295f69473d97@linux.vnet.ibm.com> <20180131131937.GA6740@dhcp22.suse.cz> <20180201134829.GL21609@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 13-02-18 12:19:18, Anshuman Khandual wrote: > On 02/01/2018 07:18 PM, Michal Hocko wrote: > > On Thu 01-02-18 08:43:34, Anshuman Khandual wrote: > > [...] > >> $dmesg | grep elf_brk > >> [ 9.571192] elf_brk 10030328 elf_bss 10030000 > >> > >> static int load_elf_binary(struct linux_binprm *bprm) > >> --------------------- > >> > >> if (unlikely (elf_brk > elf_bss)) { > >> unsigned long nbyte; > >> > >> /* There was a PT_LOAD segment with p_memsz > p_filesz > >> before this one. Map anonymous pages, if needed, > >> and clear the area. */ > >> retval = set_brk(elf_bss + load_bias, > >> elf_brk + load_bias, > >> bss_prot); > >> > >> > >> --------------------- > > > > Just a blind shot... Does the following make any difference? > > --- > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > > index 021fe78998ea..04b24d00c911 100644 > > --- a/fs/binfmt_elf.c > > +++ b/fs/binfmt_elf.c > > @@ -895,7 +895,7 @@ static int load_elf_binary(struct linux_binprm *bprm) > > the correct location in memory. */ > > for(i = 0, elf_ppnt = elf_phdata; > > i < loc->elf_ex.e_phnum; i++, elf_ppnt++) { > > - int elf_prot = 0, elf_flags; > > + int elf_prot = 0, elf_flags, elf_fixed = MAP_FIXED_NOREPLACE; > > unsigned long k, vaddr; > > unsigned long total_size = 0; > > > > @@ -927,6 +927,7 @@ static int load_elf_binary(struct linux_binprm *bprm) > > */ > > } > > } > > + elf_fixed = MAP_FIXED; > > } > > > > if (elf_ppnt->p_flags & PF_R) > > @@ -944,7 +945,7 @@ static int load_elf_binary(struct linux_binprm *bprm) > > * the ET_DYN load_addr calculations, proceed normally. > > */ > > if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) { > > - elf_flags |= MAP_FIXED_NOREPLACE; > > + elf_flags |= elf_fixed; > > } else if (loc->elf_ex.e_type == ET_DYN) { > > /* > > * This logic is run once for the first LOAD Program > > @@ -980,7 +981,7 @@ static int load_elf_binary(struct linux_binprm *bprm) > > load_bias = ELF_ET_DYN_BASE; > > if (current->flags & PF_RANDOMIZE) > > load_bias += arch_mmap_rnd(); > > - elf_flags |= MAP_FIXED_NOREPLACE; > > + elf_flags |= elf_fixed; > > } else > > load_bias = 0; > > > > > > Yeah, it does solve the problem on mmotm-2018-01-25-16-20. Thanks a lot for testing! I will post an RFC patch shortly. -- Michal Hocko SUSE Labs