Message-ID: <0000000000007ac19005f10ac1aa@google.com>
Date:   Fri, 30 Dec 2022 04:29:41 -0800
From:   syzbot <syzbot+cb1fdea540b46f0ce394@...kaller.appspotmail.com>
To:     anton@...era.com, linux-kernel@...r.kernel.org,
        linux-ntfs-dev@...ts.sourceforge.net,
        syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ntfs?] possible deadlock in map_mft_record

syzbot has found a reproducer for the following issue on:

HEAD commit:    2258c2dc850b Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1285d048480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=68e0be42c8ee4bb4
dashboard link: https://syzkaller.appspot.com/bug?extid=cb1fdea540b46f0ce394
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=15d788b8480000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15347b32480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/aee4b2292a64/disk-2258c2dc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ecfc816182c/vmlinux-2258c2dc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f24ffaf1255a/bzImage-2258c2dc.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0f6a807498b6/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cb1fdea540b46f0ce394@...kaller.appspotmail.com

loop0: detected capacity change from 0 to 4096
ntfs: volume version 3.1.
======================================================
WARNING: possible circular locking dependency detected
6.2.0-rc1-syzkaller-00043-g2258c2dc850b #0 Not tainted
------------------------------------------------------
syz-executor154/5075 is trying to acquire lock:
ffff888073152ad0 (&lcnbmp_mrec_lock_key){+.+.}-{3:3}, at: map_mft_record+0x46/0x610 fs/ntfs/mft.c:154

but task is already holding lock:
ffff88802ac261f8 (&vol->lcnbmp_lock){+.+.}-{3:3}, at: ntfs_put_super+0x36b/0xf80 fs/ntfs/super.c:2282

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&vol->lcnbmp_lock){+.+.}-{3:3}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       down_write+0x9c/0x270 kernel/locking/rwsem.c:1562
       __ntfs_cluster_free+0xd4/0x890 fs/ntfs/lcnalloc.c:862
       ntfs_cluster_free fs/ntfs/lcnalloc.h:96 [inline]
       ntfs_truncate+0x119c/0x2720 fs/ntfs/inode.c:2695
       ntfs_truncate_vfs fs/ntfs/inode.c:2862 [inline]
       ntfs_setattr+0x2b9/0x3a0 fs/ntfs/inode.c:2914
       notify_change+0xe50/0x1100 fs/attr.c:482
       do_truncate+0x200/0x2f0 fs/open.c:65
       handle_truncate fs/namei.c:3216 [inline]
       do_open fs/namei.c:3561 [inline]
       path_openat+0x272b/0x2dd0 fs/namei.c:3714
       do_file_open_root+0x339/0x790 fs/namei.c:3766
       file_open_root+0x234/0x290 fs/open.c:1290
       do_handle_open+0x565/0x950 fs/fhandle.c:232
       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

-> #0 (&lcnbmp_mrec_lock_key){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       map_mft_record+0x46/0x610 fs/ntfs/mft.c:154
       __ntfs_write_inode+0x80/0xc90 fs/ntfs/inode.c:2978
       ntfs_commit_inode fs/ntfs/inode.h:300 [inline]
       ntfs_put_super+0x3ba/0xf80 fs/ntfs/super.c:2283
       generic_shutdown_super+0x130/0x310 fs/super.c:492
       kill_block_super+0x79/0xd0 fs/super.c:1386
       deactivate_locked_super+0xa7/0xf0 fs/super.c:332
       cleanup_mnt+0x494/0x520 fs/namespace.c:1291
       task_work_run+0x243/0x300 kernel/task_work.c:179
       exit_task_work include/linux/task_work.h:38 [inline]
       do_exit+0x644/0x2150 kernel/exit.c:867
       do_group_exit+0x1fd/0x2b0 kernel/exit.c:1012
       __do_sys_exit_group kernel/exit.c:1023 [inline]
       __se_sys_exit_group kernel/exit.c:1021 [inline]
       __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1021
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&vol->lcnbmp_lock);
                               lock(&lcnbmp_mrec_lock_key);
                               lock(&vol->lcnbmp_lock);
  lock(&lcnbmp_mrec_lock_key);

 *** DEADLOCK ***

2 locks held by syz-executor154/5075:
 #0: ffff88807a03e0e0 (&type->s_umount_key#46){+.+.}-{3:3}, at: deactivate_super+0x96/0xd0 fs/super.c:362
 #1: ffff88802ac261f8 (&vol->lcnbmp_lock){+.+.}-{3:3}, at: ntfs_put_super+0x36b/0xf80 fs/ntfs/super.c:2282

stack backtrace:
CPU: 1 PID: 5075 Comm: syz-executor154 Not tainted 6.2.0-rc1-syzkaller-00043-g2258c2dc850b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
 map_mft_record+0x46/0x610 fs/ntfs/mft.c:154
 __ntfs_write_inode+0x80/0xc90 fs/ntfs/inode.c:2978
 ntfs_commit_inode fs/ntfs/inode.h:300 [inline]
 ntfs_put_super+0x3ba/0xf80 fs/ntfs/super.c:2283
 generic_shutdown_super+0x130/0x310 fs/super.c:492
 kill_block_super+0x79/0xd0 fs/super.c:1386
 deactivate_locked_super+0xa7/0xf0 fs/super.c:332
 cleanup_mnt+0x494/0x520 fs/namespace.c:1291
 task_work_run+0x243/0x300 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x644/0x2150 kernel/exit.c:867
 do_group_exit+0x1fd/0x2b0 kernel/exit.c:1012
 __do_sys_exit_group kernel/exit.c:1023 [inline]
 __se_sys_exit_group kernel/exit.c:1021 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1021
 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: 0033:0x7f1316ebea09
Code: Unable to access opcode bytes at 0x7f1316ebe9df.
RSP: 002b:00007ffe53bdb118 EFLAGS: 0000

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