From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933470AbeBMGth (ORCPT ); Tue, 13 Feb 2018 01:49:37 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51354 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933406AbeBMGte (ORCPT ); Tue, 13 Feb 2018 01:49:34 -0500 Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE To: Michal Hocko , Anshuman Khandual References: <5acba3c2-754d-e449-24ff-a72a0ad0d895@linux.vnet.ibm.com> <20180126140415.GD5027@dhcp22.suse.cz> <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> 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 From: Anshuman Khandual Date: Tue, 13 Feb 2018 12:19:18 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20180201134829.GL21609@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18021306-0040-0000-0000-0000042F2C27 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18021306-0041-0000-0000-000020D2EE39 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-13_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802130085 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.