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Date:   Sat, 22 Oct 2022 04:43:43 -0700
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Message-ID: <000000000000102c9e05eb9e12c3@google.com>
Subject: Re: [syzbot] BUG: unable to handle kernel paging request in mi_enum_attr
From:   syzbot <syzbot+28207acc70bbf3d85b74@syzkaller.appspotmail.com>
To:     almaz.alexandrovich@paragon-software.com,
        linux-kernel@vger.kernel.org, ntfs3@lists.linux.dev,
        syzkaller-bugs@googlegroups.com
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syzbot has found a reproducer for the following issue on:

HEAD commit:    440b7895c990 Merge tag 'mm-hotfixes-stable-2022-10-20' of ..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=12f15216880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=afc317c0f52ce670
dashboard link: https://syzkaller.appspot.com/bug?extid=28207acc70bbf3d85b74
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16d6496a880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13d32fc2880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/105038975fc9/disk-440b7895.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/edd7302c8fc8/vmlinux-440b7895.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7e29515d4690/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+28207acc70bbf3d85b74@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4096
ntfs3: loop0: Different NTFS' sector size (1024) and media sector size (512)
ntfs3: loop0: Mark volume as dirty due to NTFS errors
==================================================================
BUG: KASAN: use-after-free in mi_enum_attr+0x583/0x6a0 fs/ntfs3/record.c:227
Read of size 4 at addr ffff888177de6993 by task syz-executor131/3605

CPU: 0 PID: 3605 Comm: syz-executor131 Not tainted 6.1.0-rc1-syzkaller-00158-g440b7895c990 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 print_address_description+0x74/0x340 mm/kasan/report.c:284
 print_report+0x107/0x1f0 mm/kasan/report.c:395
 kasan_report+0xcd/0x100 mm/kasan/report.c:495
 mi_enum_attr+0x583/0x6a0 fs/ntfs3/record.c:227
 ni_enum_attr_ex+0x2f6/0x6d0 fs/ntfs3/frecord.c:259
 ntfs_read_mft fs/ntfs3/inode.c:114 [inline]
 ntfs_iget5+0x1d3e/0x36f0 fs/ntfs3/inode.c:501
 ntfs_fill_super+0x3b55/0x42a0 fs/ntfs3/super.c:1195
 get_tree_bdev+0x400/0x620 fs/super.c:1323
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f43fe5afaca
Code: 48 c7 c2 c0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 f8 03 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd57724258 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f43fe5afaca
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd57724270
RBP: 00007ffd57724270 R08: 00007ffd577242b0 R09: 00007ffd577242e0
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000004
R13: 00007ffd577242b0 R14: 0000000000000109 R15: 0000000020001ad8
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0005df7980 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x177de6
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea0005df7988 ffffea0005df7988 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff888177de6880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888177de6900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888177de6980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff888177de6a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888177de6a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================