From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66766C43142 for ; Thu, 2 Aug 2018 19:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10B6221567 for ; Thu, 2 Aug 2018 19:23:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 10B6221567 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=iogearbox.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727153AbeHBVPg (ORCPT ); Thu, 2 Aug 2018 17:15:36 -0400 Received: from www62.your-server.de ([213.133.104.62]:45888 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726177AbeHBVPg (ORCPT ); Thu, 2 Aug 2018 17:15:36 -0400 Received: from [78.46.172.2] (helo=sslproxy05.your-server.de) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85_2) (envelope-from ) id 1flJBd-0002Ty-FU; Thu, 02 Aug 2018 21:23:01 +0200 Received: from [62.203.87.61] (helo=linux.home) by sslproxy05.your-server.de with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1flJBd-000ODf-AE; Thu, 02 Aug 2018 21:23:01 +0200 Subject: Re: KASAN: use-after-free Read in bpf_cgroup_storage_release To: syzbot , ast@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, guro@fb.com References: <000000000000f3b1570572779079@google.com> From: Daniel Borkmann Message-ID: <1b3dde38-549e-43ed-d3f6-18b451444d2f@iogearbox.net> Date: Thu, 2 Aug 2018 21:23:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <000000000000f3b1570572779079@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.100.0/24806/Thu Aug 2 18:43:24 2018) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ +Roman ] On 08/02/2018 07:59 PM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit:    fc2a3b5dd618 Merge branch 'bpf-cgroup-local-storage' > git tree:       bpf-next > console output: https://syzkaller.appspot.com/x/log.txt?x=17a6a1c8400000 > kernel config:  https://syzkaller.appspot.com/x/.config?x=3bfcc1651962483 > dashboard link: https://syzkaller.appspot.com/bug?extid=25554ab865a12b51c66f > compiler:       gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=12c4b9b4400000 > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13e9d6f0400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+25554ab865a12b51c66f@syzkaller.appspotmail.com > > ================================================================== > BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] > BUG: KASAN: use-after-free in do_raw_spin_lock+0x1c0/0x200 kernel/locking/spinlock_debug.c:112 > Read of size 4 at addr ffff8801c4723644 by task syz-executor865/9746 > > CPU: 0 PID: 9746 Comm: syz-executor865 Not tainted 4.18.0-rc5+ #68 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: >  __dump_stack lib/dump_stack.c:77 [inline] >  dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 >  print_address_description+0x6c/0x20b mm/kasan/report.c:256 >  kasan_report_error mm/kasan/report.c:354 [inline] >  kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 >  __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 >  debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline] >  do_raw_spin_lock+0x1c0/0x200 kernel/locking/spinlock_debug.c:112 >  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline] >  _raw_spin_lock_bh+0x39/0x40 kernel/locking/spinlock.c:168 >  spin_lock_bh include/linux/spinlock.h:315 [inline] >  bpf_cgroup_storage_release+0x2c/0x110 kernel/bpf/local_storage.c:276 >  free_used_maps+0x81/0x200 kernel/bpf/syscall.c:961 >  bpf_prog_load+0x17ba/0x1c90 kernel/bpf/syscall.c:1414 >  __do_sys_bpf kernel/bpf/syscall.c:2338 [inline] >  __se_sys_bpf kernel/bpf/syscall.c:2300 [inline] >  __x64_sys_bpf+0x36c/0x510 kernel/bpf/syscall.c:2300 >  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >  entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x4490d9 > Code: e8 8c bb 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 4b 00 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f6096d1ace8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 > RAX: ffffffffffffffda RBX: 00000000006e5a08 RCX: 00000000004490d9 > RDX: 0000000000000048 RSI: 000000002001a840 RDI: 0000000000000005 > RBP: 00000000006e5a00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e5a0c > R13: 00007fffd579e24f R14: 00007f6096d1b9c0 R15: 0000000000000019 > > Allocated by task 9746: >  save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >  set_track mm/kasan/kasan.c:460 [inline] >  kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 >  kmem_cache_alloc_node_trace+0x150/0x770 mm/slab.c:3663 >  kmalloc_node include/linux/slab.h:551 [inline] >  cgroup_storage_map_alloc+0x26d/0x400 kernel/bpf/local_storage.c:209 >  find_and_alloc_map kernel/bpf/syscall.c:129 [inline] >  map_create+0x37f/0xe20 kernel/bpf/syscall.c:481 >  __do_sys_bpf kernel/bpf/syscall.c:2323 [inline] >  __se_sys_bpf kernel/bpf/syscall.c:2300 [inline] >  __x64_sys_bpf+0x303/0x510 kernel/bpf/syscall.c:2300 >  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >  entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 19: >  save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >  set_track mm/kasan/kasan.c:460 [inline] >  __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 >  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 >  __cache_free mm/slab.c:3498 [inline] >  kfree+0xd9/0x260 mm/slab.c:3813 >  cgroup_storage_map_free+0x16e/0x210 kernel/bpf/local_storage.c:234 >  bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:290 >  process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 >  worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 >  kthread+0x345/0x410 kernel/kthread.c:246 >  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > The buggy address belongs to the object at ffff8801c4723540 >  which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 260 bytes inside of >  512-byte region [ffff8801c4723540, ffff8801c4723740) > The buggy address belongs to the page: > page:ffffea000711c8c0 count:1 mapcount:0 mapping:ffff8801dac00940 index:0xffff8801c4723a40 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0007299088 ffffea00072247c8 ffff8801dac00940 > raw: ffff8801c4723a40 ffff8801c4723040 0000000100000004 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: >  ffff8801c4723500: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >  ffff8801c4723580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ffff8801c4723600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >                                            ^ >  ffff8801c4723680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >  ffff8801c4723700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches