From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751277AbeECHiI (ORCPT ); Thu, 3 May 2018 03:38:08 -0400 Received: from mail-it0-f70.google.com ([209.85.214.70]:59973 "EHLO mail-it0-f70.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbeECHiC (ORCPT ); Thu, 3 May 2018 03:38:02 -0400 X-Google-Smtp-Source: AB8JxZq53+m+Qws74df298FTigGAN2VqgBPlcf8r6rekQn+QFrJCOuo9nE5nhi7gxbQJ3S31jYa3VV1dD3KjzE2cS8fcTPq8kucl MIME-Version: 1.0 Date: Thu, 03 May 2018 00:38:02 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000008631d3056b4848e1@google.com> Subject: KASAN: use-after-free Read in ext4_data_block_valid From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu 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 found the following crash on: HEAD commit: 6da6c0db5316 Linux v4.17-rc3 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?id=5004455753809920 kernel config: https://syzkaller.appspot.com/x/.config?id=6493557782959164711 dashboard link: https://syzkaller.appspot.com/bug?extid=1e470567330b7ad711d5 compiler: gcc (GCC) 8.0.1 20180413 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+1e470567330b7ad711d5@syzkaller.appspotmail.com EXT4-fs (sda1): re-mounted. Opts: noblock_validity, ================================================================== BUG: KASAN: use-after-free in ext4_data_block_valid+0x2df/0x340 fs/ext4/block_validity.c:211 Read of size 8 at addr ffff8801cc464750 by task sh/17001 CPU: 0 PID: 17001 Comm: sh Not tainted 4.17.0-rc3+ #25 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+0x1b9/0x294 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_load8_noabort+0x14/0x20 mm/kasan/report.c:433 ext4_data_block_valid+0x2df/0x340 fs/ext4/block_validity.c:211 __check_block_validity.constprop.78+0xc1/0x200 fs/ext4/inode.c:402 ext4_map_blocks+0x100b/0x1b40 fs/ext4/inode.c:592 ext4_getblk+0x4d5/0x600 fs/ext4/inode.c:966 ext4_bread_batch+0x7f/0x450 fs/ext4/inode.c:1036 ext4_find_entry+0xd2a/0x1b50 fs/ext4/namei.c:1424 ext4_lookup+0x149/0x730 fs/ext4/namei.c:1556 lookup_open+0x71d/0x1b40 fs/namei.c:3165 do_last fs/namei.c:3277 [inline] path_openat+0x2211/0x4e20 fs/namei.c:3501 do_filp_open+0x249/0x350 fs/namei.c:3535 do_open_execat+0x1f6/0x650 fs/exec.c:854 do_execveat_common.isra.34+0x920/0x2590 fs/exec.c:1755 do_execve fs/exec.c:1862 [inline] __do_sys_execve fs/exec.c:1943 [inline] __se_sys_execve fs/exec.c:1938 [inline] __x64_sys_execve+0x8d/0xb0 fs/exec.c:1938 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f06cf7c3207 RSP: 002b:00007ffdedae6df8 EFLAGS: 00000202 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000000000061c3e8 RCX: 00007f06cf7c3207 RDX: 00000000021a51d0 RSI: 000000000061c3e8 RDI: 00000000021a51e8 RBP: 00000000021a51e8 R08: 000000000061c370 R09: 00007f06cf83aa00 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000021a51d0 R13: 00000000021a51d0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 1: 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 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 add_system_zone+0x2e8/0x5f0 fs/ext4/block_validity.c:85 ext4_setup_system_zone+0x208/0x520 fs/ext4/block_validity.c:169 ext4_fill_super+0x790d/0xd810 fs/ext4/super.c:4257 mount_bdev+0x30c/0x3e0 fs/super.c:1164 ext4_mount+0x34/0x40 fs/ext4/super.c:5740 mount_fs+0xae/0x328 fs/super.c:1267 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x564/0x3070 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 do_mount_root+0x35/0x1d3 init/do_mounts.c:366 mount_block_root+0x3d1/0x71f init/do_mounts.c:395 mount_root+0x2c8/0x2fb init/do_mounts.c:540 prepare_namespace+0x26c/0x2ab init/do_mounts.c:599 kernel_init_freeable+0x570/0x58e init/main.c:1146 kernel_init+0x11/0x1b3 init/main.c:1053 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Freed by task 16987: 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] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 ext4_release_system_zone+0x7c/0x110 fs/ext4/block_validity.c:187 ext4_setup_system_zone+0x3ef/0x520 fs/ext4/block_validity.c:151 ext4_remount+0x1420/0x2480 fs/ext4/super.c:5192 do_remount_sb+0x348/0x790 fs/super.c:875 do_remount fs/namespace.c:2339 [inline] do_mount+0x1445/0x3070 fs/namespace.c:2839 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801cc464738 which belongs to the cache ext4_system_zone of size 40 The buggy address is located 24 bytes inside of 40-byte region [ffff8801cc464738, ffff8801cc464760) The buggy address belongs to the page: page:ffffea0007311900 count:1 mapcount:0 mapping:ffff8801cc464000 index:0xffff8801cc464fb9 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffff8801cc464000 ffff8801cc464fb9 0000000100000007 raw: ffff8801d3e24b38 ffff8801d3e24b38 ffff8801d3e23080 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801cc464600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801cc464680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801cc464700: fc fc fc fc fc fc fc fb fb fb fb fb fc fc fb fb ^ ffff8801cc464780: fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb fb ffff8801cc464800: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc ================================================================== --- This bug is generated by a bot. 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