From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752851AbeDAIVE (ORCPT ); Sun, 1 Apr 2018 04:21:04 -0400 Received: from mail-io0-f198.google.com ([209.85.223.198]:48608 "EHLO mail-io0-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751168AbeDAIVC (ORCPT ); Sun, 1 Apr 2018 04:21:02 -0400 X-Google-Smtp-Source: AIpwx48QAbCDTwUNdoY32Tvf6fRwqMkBgZYyWzSRwvZS9Ofy/9r1U9YIn+efSoi4QX/YuAUCN51FX41sEQY8ZJ6L9zJ/kJPRU8z+ MIME-Version: 1.0 Date: Sun, 01 Apr 2018 01:21:01 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <94eb2c06406c59cccc0568c527c2@google.com> Subject: KASAN: use-after-free Read in alloc_pid From: syzbot To: akpm@linux-foundation.org, dhowells@redhat.com, ebiederm@xmission.com, gs051095@gmail.com, linux-kernel@vger.kernel.org, oleg@redhat.com, pasha.tatashin@oracle.com, riel@redhat.com, rppt@linux.vnet.ibm.com, syzkaller-bugs@googlegroups.com, wangkefeng.wang@huawei.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot hit the following crash on upstream commit 9dd2326890d89a5179967c947dab2bab34d7ddee (Fri Mar 30 17:29:47 2018 +0000) Merge tag 'ceph-for-4.16-rc8' of git://github.com/ceph/ceph-client syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=7a1cff37dbbef9e7ba4c So far this crash happened 4 times on upstream. Unfortunately, I don't have any reproducer for this crash yet. Raw console output: https://syzkaller.appspot.com/x/log.txt?id=6588786309857280 Kernel config: https://syzkaller.appspot.com/x/.config?id=-2760467897697295172 compiler: gcc (GCC) 7.1.1 20170620 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+7a1cff37dbbef9e7ba4c@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer. R10: 0000000020000900 R11: 0000000000000246 R12: 0000000000000015 R13: 0000000000000051 R14: 00000000006f2838 R15: 0000000000000028 ================================================================== BUG: KASAN: use-after-free in alloc_pid+0x9a6/0xa00 kernel/pid.c:236 Read of size 4 at addr ffff8801b56d0088 by task syz-executor4/3533 CPU: 1 PID: 3533 Comm: syz-executor4 Not tainted 4.16.0-rc7+ #372 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 alloc_pid+0x9a6/0xa00 kernel/pid.c:236 copy_process.part.38+0x2516/0x4bd0 kernel/fork.c:1807 copy_process kernel/fork.c:1606 [inline] _do_fork+0x1f7/0xf70 kernel/fork.c:2087 SYSC_clone kernel/fork.c:2194 [inline] SyS_clone+0x37/0x50 kernel/fork.c:2188 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454e79 RSP: 002b:00007f6165b9ac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f6165b9b6d4 RCX: 0000000000454e79 RDX: 00000000200008c0 RSI: 0000000020000800 RDI: 000000002000c100 RBP: 000000000072bea0 R08: 0000000020000940 R09: 0000000000000000 R10: 0000000020000900 R11: 0000000000000246 R12: 0000000000000015 R13: 0000000000000051 R14: 00000000006f2838 R15: 0000000000000028 Allocated by task 3533: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3542 kmem_cache_zalloc include/linux/slab.h:691 [inline] create_pid_namespace kernel/pid_namespace.c:116 [inline] copy_pid_ns+0x257/0xc60 kernel/pid_namespace.c:175 create_new_namespaces+0x307/0x880 kernel/nsproxy.c:94 copy_namespaces+0x340/0x400 kernel/nsproxy.c:165 copy_process.part.38+0x2380/0x4bd0 kernel/fork.c:1796 copy_process kernel/fork.c:1606 [inline] _do_fork+0x1f7/0xf70 kernel/fork.c:2087 SYSC_clone kernel/fork.c:2194 [inline] SyS_clone+0x37/0x50 kernel/fork.c:2188 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 3539: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3486 [inline] kmem_cache_free+0x83/0x2a0 mm/slab.c:3744 delayed_free_pidns+0x82/0xb0 kernel/pid_namespace.c:157 __rcu_reclaim kernel/rcu/rcu.h:172 [inline] rcu_do_batch kernel/rcu/tree.c:2674 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2933 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2900 [inline] rcu_process_callbacks+0xd6c/0x17f0 kernel/rcu/tree.c:2917 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 The buggy address belongs to the object at ffff8801b56d0040 which belongs to the cache pid_namespace of size 240 The buggy address is located 72 bytes inside of 240-byte region [ffff8801b56d0040, ffff8801b56d0130) The buggy address belongs to the page: page:ffffea0006d5b400 count:1 mapcount:0 mapping:ffff8801b56d0040 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801b56d0040 0000000000000000 000000010000000d raw: ffffea00074458a0 ffffea00073389e0 ffff8801d40b2c00 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b56cff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801b56d0000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb > ffff8801b56d0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b56d0100: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fb fb ffff8801b56d0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a dumb bot. It may contain errors. See https://goo.gl/tpsmEJ for details. Direct all questions to syzkaller@googlegroups.com. syzbot will keep track of this bug report. If you forgot to add the Reported-by tag, once the fix for this bug is merged into any tree, please reply to this email with: #syz fix: exact-commit-title To mark this as a duplicate of another syzbot report, please reply with: #syz dup: exact-subject-of-another-report If it's a one-off invalid bug report, please reply with: #syz invalid Note: if the crash happens again, it will cause creation of a new bug report. Note: all commands must start from beginning of the line in the email body.