From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f71.google.com ([209.85.166.71]:32778 "EHLO mail-io1-f71.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726772AbfABKbF (ORCPT ); Wed, 2 Jan 2019 05:31:05 -0500 Received: by mail-io1-f71.google.com with SMTP id p21so6606728iog.0 for ; Wed, 02 Jan 2019 02:31:04 -0800 (PST) MIME-Version: 1.0 Date: Wed, 02 Jan 2019 02:31:04 -0800 Message-ID: <000000000000a415f5057e772463@google.com> Subject: KASAN: use-after-free Read in posix_lock_inode From: syzbot To: bfields@fieldses.org, jlayton@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hello, syzbot found the following crash on: HEAD commit: e1ef035d272e Merge tag 'armsoc-defconfig' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16bb4c4b400000 kernel config: https://syzkaller.appspot.com/x/.config?x=9c6a26e22579190b dashboard link: https://syzkaller.appspot.com/bug?extid=239d99847eb49ecb3899 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=128aa377400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+239d99847eb49ecb3899@syzkaller.appspotmail.com IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready 8021q: adding VLAN 0 to HW filter on device batadv0 8021q: adding VLAN 0 to HW filter on device batadv0 ================================================================== BUG: KASAN: use-after-free in what_owner_is_waiting_for fs/locks.c:1000 [inline] BUG: KASAN: use-after-free in posix_locks_deadlock fs/locks.c:1023 [inline] BUG: KASAN: use-after-free in posix_lock_inode+0x1f9e/0x2750 fs/locks.c:1163 Read of size 8 at addr ffff88808791b000 by task syz-executor2/10100 CPU: 1 PID: 10100 Comm: syz-executor2 Not tainted 4.20.0+ #3 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 what_owner_is_waiting_for fs/locks.c:1000 [inline] posix_locks_deadlock fs/locks.c:1023 [inline] posix_lock_inode+0x1f9e/0x2750 fs/locks.c:1163 posix_lock_file fs/locks.c:1346 [inline] vfs_lock_file fs/locks.c:2314 [inline] vfs_lock_file+0xc7/0xf0 fs/locks.c:2309 do_lock_file_wait.part.0+0xe5/0x260 fs/locks.c:2328 do_lock_file_wait fs/locks.c:2324 [inline] fcntl_setlk+0x2f1/0xfe0 fs/locks.c:2413 do_fcntl+0x843/0x12b0 fs/fcntl.c:370 __do_sys_fcntl fs/fcntl.c:463 [inline] __se_sys_fcntl fs/fcntl.c:448 [inline] __x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f58bbb50c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000048 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000020000140 RSI: 0000000000000007 RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f58bbb516d4 R13: 00000000004be5f0 R14: 00000000004ceab0 R15: 00000000ffffffff Allocated by task 10100: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:397 kmem_cache_alloc+0x12d/0x710 mm/slab.c:3541 kmem_cache_zalloc include/linux/slab.h:730 [inline] locks_alloc_lock+0x8e/0x2f0 fs/locks.c:344 fcntl_setlk+0xa9/0xfe0 fs/locks.c:2362 do_fcntl+0x843/0x12b0 fs/fcntl.c:370 __do_sys_fcntl fs/fcntl.c:463 [inline] __se_sys_fcntl fs/fcntl.c:448 [inline] __x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 10100: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3747 locks_free_lock+0x27a/0x3f0 fs/locks.c:381 fcntl_setlk+0x7b5/0xfe0 fs/locks.c:2439 do_fcntl+0x843/0x12b0 fs/fcntl.c:370 __do_sys_fcntl fs/fcntl.c:463 [inline] __se_sys_fcntl fs/fcntl.c:448 [inline] __x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88808791b000 which belongs to the cache file_lock_cache of size 264 The buggy address is located 0 bytes inside of 264-byte region [ffff88808791b000, ffff88808791b108) The buggy address belongs to the page: page:ffffea00021e46c0 count:1 mapcount:0 mapping:ffff8880aa16a1c0 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002333508 ffffea00021d76c8 ffff8880aa16a1c0 raw: 0000000000000000 ffff88808791b000 000000010000000c 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808791af00: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc ffff88808791af80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff88808791b000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808791b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808791b100: fb fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb 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