From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751984AbeAaFFx (ORCPT ); Wed, 31 Jan 2018 00:05:53 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60034 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751553AbeAaFFu (ORCPT ); Wed, 31 Jan 2018 00:05:50 -0500 Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE To: Michal Hocko , Michael Ellerman , Anshuman Khandual References: <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> <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> Cc: "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: Wed, 31 Jan 2018 10:35:38 +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: <20180130094205.GS21609@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18013105-0012-0000-0000-000005A9ACB1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18013105-0013-0000-0000-000019254C26 Message-Id: <5eccdc1b-6a10-b48a-c63f-295f69473d97@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-01-31_01:,, 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=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1801310065 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/30/2018 03:12 PM, Michal Hocko wrote: > On Tue 30-01-18 14:35:12, Michael Ellerman wrote: >> Michal Hocko writes: >> >>> On Mon 29-01-18 11:02:09, Anshuman Khandual wrote: >>>> On 01/29/2018 08:17 AM, Anshuman Khandual wrote: >>>>> On 01/26/2018 07:34 PM, Michal Hocko wrote: >>>>>> 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. >> ... >>>> >>>> Okay, this colliding VMA seems to be getting loaded from load_elf_binary() >>>> function as well. >>>> >>>> [ 9.422410] vma c000001fceedbc40 start 0000000010030000 end 0000000010040000 >>>> next c000001fceedbe80 prev c000001fceedb700 mm c000001fceea8200 >>>> prot 8000000000000104 anon_vma (null) vm_ops (null) >>>> pgoff 1003 file (null) private_data (null) >>>> flags: 0x100073(read|write|mayread|maywrite|mayexec|account) >>>> [ 9.422576] CPU: 46 PID: 7457 Comm: sed Not tainted 4.14.0-dirty #158 >>>> [ 9.422610] Call Trace: >>>> [ 9.422623] [c000001fdc4f79b0] [c000000000b17ac0] dump_stack+0xb0/0xf0 (unreliable) >>>> [ 9.422670] [c000001fdc4f79f0] [c0000000002dafb8] do_brk_flags+0x2d8/0x440 >>>> [ 9.422708] [c000001fdc4f7ac0] [c0000000002db3d0] vm_brk_flags+0x80/0x130 >>>> [ 9.422747] [c000001fdc4f7b20] [c0000000003d23a4] set_brk+0x80/0xdc >>>> [ 9.422785] [c000001fdc4f7b60] [c0000000003d1f24] load_elf_binary+0x1304/0x158c >>>> [ 9.422830] [c000001fdc4f7c80] [c00000000035d3e0] search_binary_handler+0xd0/0x270 >>>> [ 9.422881] [c000001fdc4f7d10] [c00000000035f338] do_execveat_common.isra.31+0x658/0x890 >>>> [ 9.422926] [c000001fdc4f7df0] [c00000000035f980] SyS_execve+0x40/0x50 >>>> [ 9.423588] [c000001fdc4f7e30] [c00000000000b220] system_call+0x58/0x6c >>>> >>>> which is getting hit after adding some more debug. >>> >>> Voila! So your binary simply overrides brk by elf segments. That sounds >>> like the exactly the thing that the patch is supposed to protect from. >>> Why this is the case I dunno. It is just clear that either brk or >>> elf base are not put to the proper place. Something to get fixed. You >>> are probably just lucky that brk allocations do not spil over to elf >>> mappings. >> >> It is something to get fixed, but we can't retrospectively fix the >> existing binaries sitting on peoples' systems. > > Yeah. Can we identify those somehow? Are they something people can > easily come across? > >> Possibly powerpc arch code is doing something with the mmap layout or >> something else that is confusing the ELF loader, in which case we should >> fix that. > > Yes this definitely should be fixed. How can elf loader completely > overlap brk mapping? > >> But if not then the only solution is for the ELF loader to be more >> tolerant of this situation. >> >> So for 4.16 this patch either needs to be dropped, or reworked such that >> powerpc can opt out of it. > > Yeah, let's hold on merging this until we understand what the heck is > going on here. If this turnes to be unfixable I will think of a way for > ppc to opt out. > > Anshuman, could you try to run > sed 's@^@@' /proc/self/smaps > on a system with MAP_FIXED_NOREPLACE reverted? > After reverting the following commits from mmotm-2018-01-25-16-20 tag. 67caea694ba5965a52a61fdad495d847f03c4025 ("mm-introduce-map_fixed_safe-fix") 64da2e0c134ecf3936a4c36b949bcf2cdc98977e ("fs-elf-drop-map_fixed-usage-from-elf_map-fix-fix") 645983ab6ca7fd644f52b4c55462b91940012595 ("mm: don't use the same value for MAP_FIXED_NOREPLACE and MAP_SYNC") d77bab291ac435aab91fa214b85efa74a26c9c22 ("fs-elf-drop-map_fixed-usage-from-elf_map-checkpatch-fixes") a75c5f92d9ecb21d3299cc7db48e401cbf335c34 ("fs, elf: drop MAP_FIXED usage from elf_map") 00906d029ffe515221e3939b222c237026af2903 ("mm: introduce MAP_FIXED_NOREPLACE") $sed 's@^@@' /proc/self/smaps ------------------------------------------- 10000000-10020000 r-xp 00000000 fd:00 10558 /usr/bin/sed Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 128 kB Pss: 128 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 128 kB Private_Dirty: 0 kB Referenced: 128 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 128 kB VmFlags: rd ex mr mw me dw 10020000-10030000 r--p 00010000 fd:00 10558 /usr/bin/sed Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me dw ac 10030000-10040000 rw-p 00020000 fd:00 10558 /usr/bin/sed Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me dw ac 2cbb0000-2cbe0000 rw-p 00000000 00:00 0 [heap] Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff7f9c0000-7fff7f9e0000 rw-p 00000000 00:00 0 Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 128 kB Pss: 128 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 128 kB Referenced: 128 kB Anonymous: 128 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 128 kB VmFlags: rd wr mr mw me ac 7fff7f9e0000-7fff86280000 r--p 00000000 fd:00 33660156 /usr/lib/locale/locale-archive Size: 107136 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 384 kB Pss: 37 kB Shared_Clean: 384 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 384 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 37 kB VmFlags: rd mr mw me 7fff86280000-7fff86290000 r-xp 00000000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 2 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 2 kB VmFlags: rd ex mr mw me 7fff86290000-7fff862a0000 r--p 00000000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff862a0000-7fff862b0000 rw-p 00010000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff862b0000-7fff86300000 r-xp 00000000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 320 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 2 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 2 kB VmFlags: rd ex mr mw me 7fff86300000-7fff86310000 r--p 00040000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86310000-7fff86320000 rw-p 00050000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86320000-7fff864f0000 r-xp 00000000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 1856 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 1280 kB Pss: 45 kB Shared_Clean: 1280 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 1280 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 45 kB VmFlags: rd ex mr mw me 7fff864f0000-7fff86500000 r--p 001c0000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86500000-7fff86510000 rw-p 001d0000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86510000-7fff86540000 r-xp 00000000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 192 kB Pss: 8 kB Shared_Clean: 192 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 192 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 8 kB VmFlags: rd ex mr mw me 7fff86540000-7fff86550000 r--p 00020000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86550000-7fff86560000 rw-p 00030000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86560000-7fff86570000 r--s 00000000 fd:00 67194934 /usr/lib64/gconv/gconv-modules.cache Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 12 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 12 kB VmFlags: rd mr me ms 7fff86570000-7fff86590000 r-xp 00000000 00:00 0 [vdso] Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 1 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 1 kB VmFlags: rd ex mr mw me de 7fff86590000-7fff865c0000 r-xp 00000000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 192 kB Pss: 6 kB Shared_Clean: 192 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 192 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 6 kB VmFlags: rd ex mr mw me dw 7fff865c0000-7fff865d0000 r--p 00020000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me dw ac 7fff865d0000-7fff865e0000 rw-p 00030000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me dw ac 7fffd27a0000-7fffd27d0000 rw-p 00000000 00:00 0 [stack] Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me gd ac From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: ppc elf_map breakage with MAP_FIXED_NOREPLACE To: Michal Hocko , Michael Ellerman , Anshuman Khandual References: <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> <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> Cc: "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: Wed, 31 Jan 2018 10:35:38 +0530 MIME-Version: 1.0 In-Reply-To: <20180130094205.GS21609@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: <5eccdc1b-6a10-b48a-c63f-295f69473d97@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: On 01/30/2018 03:12 PM, Michal Hocko wrote: > On Tue 30-01-18 14:35:12, Michael Ellerman wrote: >> Michal Hocko writes: >> >>> On Mon 29-01-18 11:02:09, Anshuman Khandual wrote: >>>> On 01/29/2018 08:17 AM, Anshuman Khandual wrote: >>>>> On 01/26/2018 07:34 PM, Michal Hocko wrote: >>>>>> 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. >> ... >>>> >>>> Okay, this colliding VMA seems to be getting loaded from load_elf_binary() >>>> function as well. >>>> >>>> [ 9.422410] vma c000001fceedbc40 start 0000000010030000 end 0000000010040000 >>>> next c000001fceedbe80 prev c000001fceedb700 mm c000001fceea8200 >>>> prot 8000000000000104 anon_vma (null) vm_ops (null) >>>> pgoff 1003 file (null) private_data (null) >>>> flags: 0x100073(read|write|mayread|maywrite|mayexec|account) >>>> [ 9.422576] CPU: 46 PID: 7457 Comm: sed Not tainted 4.14.0-dirty #158 >>>> [ 9.422610] Call Trace: >>>> [ 9.422623] [c000001fdc4f79b0] [c000000000b17ac0] dump_stack+0xb0/0xf0 (unreliable) >>>> [ 9.422670] [c000001fdc4f79f0] [c0000000002dafb8] do_brk_flags+0x2d8/0x440 >>>> [ 9.422708] [c000001fdc4f7ac0] [c0000000002db3d0] vm_brk_flags+0x80/0x130 >>>> [ 9.422747] [c000001fdc4f7b20] [c0000000003d23a4] set_brk+0x80/0xdc >>>> [ 9.422785] [c000001fdc4f7b60] [c0000000003d1f24] load_elf_binary+0x1304/0x158c >>>> [ 9.422830] [c000001fdc4f7c80] [c00000000035d3e0] search_binary_handler+0xd0/0x270 >>>> [ 9.422881] [c000001fdc4f7d10] [c00000000035f338] do_execveat_common.isra.31+0x658/0x890 >>>> [ 9.422926] [c000001fdc4f7df0] [c00000000035f980] SyS_execve+0x40/0x50 >>>> [ 9.423588] [c000001fdc4f7e30] [c00000000000b220] system_call+0x58/0x6c >>>> >>>> which is getting hit after adding some more debug. >>> >>> Voila! So your binary simply overrides brk by elf segments. That sounds >>> like the exactly the thing that the patch is supposed to protect from. >>> Why this is the case I dunno. It is just clear that either brk or >>> elf base are not put to the proper place. Something to get fixed. You >>> are probably just lucky that brk allocations do not spil over to elf >>> mappings. >> >> It is something to get fixed, but we can't retrospectively fix the >> existing binaries sitting on peoples' systems. > > Yeah. Can we identify those somehow? Are they something people can > easily come across? > >> Possibly powerpc arch code is doing something with the mmap layout or >> something else that is confusing the ELF loader, in which case we should >> fix that. > > Yes this definitely should be fixed. How can elf loader completely > overlap brk mapping? > >> But if not then the only solution is for the ELF loader to be more >> tolerant of this situation. >> >> So for 4.16 this patch either needs to be dropped, or reworked such that >> powerpc can opt out of it. > > Yeah, let's hold on merging this until we understand what the heck is > going on here. If this turnes to be unfixable I will think of a way for > ppc to opt out. > > Anshuman, could you try to run > sed 's@^@@' /proc/self/smaps > on a system with MAP_FIXED_NOREPLACE reverted? > After reverting the following commits from mmotm-2018-01-25-16-20 tag. 67caea694ba5965a52a61fdad495d847f03c4025 ("mm-introduce-map_fixed_safe-fix") 64da2e0c134ecf3936a4c36b949bcf2cdc98977e ("fs-elf-drop-map_fixed-usage-from-elf_map-fix-fix") 645983ab6ca7fd644f52b4c55462b91940012595 ("mm: don't use the same value for MAP_FIXED_NOREPLACE and MAP_SYNC") d77bab291ac435aab91fa214b85efa74a26c9c22 ("fs-elf-drop-map_fixed-usage-from-elf_map-checkpatch-fixes") a75c5f92d9ecb21d3299cc7db48e401cbf335c34 ("fs, elf: drop MAP_FIXED usage from elf_map") 00906d029ffe515221e3939b222c237026af2903 ("mm: introduce MAP_FIXED_NOREPLACE") $sed 's@^@@' /proc/self/smaps ------------------------------------------- 10000000-10020000 r-xp 00000000 fd:00 10558 /usr/bin/sed Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 128 kB Pss: 128 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 128 kB Private_Dirty: 0 kB Referenced: 128 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 128 kB VmFlags: rd ex mr mw me dw 10020000-10030000 r--p 00010000 fd:00 10558 /usr/bin/sed Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me dw ac 10030000-10040000 rw-p 00020000 fd:00 10558 /usr/bin/sed Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me dw ac 2cbb0000-2cbe0000 rw-p 00000000 00:00 0 [heap] Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff7f9c0000-7fff7f9e0000 rw-p 00000000 00:00 0 Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 128 kB Pss: 128 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 128 kB Referenced: 128 kB Anonymous: 128 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 128 kB VmFlags: rd wr mr mw me ac 7fff7f9e0000-7fff86280000 r--p 00000000 fd:00 33660156 /usr/lib/locale/locale-archive Size: 107136 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 384 kB Pss: 37 kB Shared_Clean: 384 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 384 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 37 kB VmFlags: rd mr mw me 7fff86280000-7fff86290000 r-xp 00000000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 2 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 2 kB VmFlags: rd ex mr mw me 7fff86290000-7fff862a0000 r--p 00000000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff862a0000-7fff862b0000 rw-p 00010000 fd:00 33660115 /usr/lib64/libdl-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff862b0000-7fff86300000 r-xp 00000000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 320 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 2 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 2 kB VmFlags: rd ex mr mw me 7fff86300000-7fff86310000 r--p 00040000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86310000-7fff86320000 rw-p 00050000 fd:00 33594504 /usr/lib64/libpcre.so.1.2.0 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86320000-7fff864f0000 r-xp 00000000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 1856 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 1280 kB Pss: 45 kB Shared_Clean: 1280 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 1280 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 45 kB VmFlags: rd ex mr mw me 7fff864f0000-7fff86500000 r--p 001c0000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86500000-7fff86510000 rw-p 001d0000 fd:00 33660109 /usr/lib64/libc-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86510000-7fff86540000 r-xp 00000000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 192 kB Pss: 8 kB Shared_Clean: 192 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 192 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 8 kB VmFlags: rd ex mr mw me 7fff86540000-7fff86550000 r--p 00020000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me ac 7fff86550000-7fff86560000 rw-p 00030000 fd:00 33594516 /usr/lib64/libselinux.so.1 Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me ac 7fff86560000-7fff86570000 r--s 00000000 fd:00 67194934 /usr/lib64/gconv/gconv-modules.cache Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 12 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 12 kB VmFlags: rd mr me ms 7fff86570000-7fff86590000 r-xp 00000000 00:00 0 [vdso] Size: 128 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 1 kB Shared_Clean: 64 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 64 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 1 kB VmFlags: rd ex mr mw me de 7fff86590000-7fff865c0000 r-xp 00000000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 192 kB Pss: 6 kB Shared_Clean: 192 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 192 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 6 kB VmFlags: rd ex mr mw me dw 7fff865c0000-7fff865d0000 r--p 00020000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd mr mw me dw ac 7fff865d0000-7fff865e0000 rw-p 00030000 fd:00 33660102 /usr/lib64/ld-2.17.so Size: 64 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me dw ac 7fffd27a0000-7fffd27d0000 rw-p 00000000 00:00 0 [stack] Size: 192 kB KernelPageSize: 64 kB MMUPageSize: 64 kB Rss: 64 kB Pss: 64 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 64 kB Referenced: 64 kB Anonymous: 64 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB Locked: 64 kB VmFlags: rd wr mr mw me gd ac -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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