[syzbot] [ntfs3?] WARNING: bad unlock balance in ntfs_readdir

[syzbot] [ntfs3?] WARNING: bad unlock balance in ntfs_readdir

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3d229ce89862 Add linux-next specific files for 20261019
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16e52e7f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a028e57b630bb4be
dashboard link: https://syzkaller.appspot.com/bug?extid=5c0ed4f2974a8b100ed4
compiler:       Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17e61831580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1099cc95580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/412cf9c202de/disk-3d229ce8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e186f12d19de/vmlinux-3d229ce8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fa13a836daa/bzImage-3d229ce8.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/c9aad314cb9a/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5c0ed4f2974a8b100ed4@syzkaller.appspotmail.com

ntfs3(loop0): Failed to load $Extend (-22).
ntfs3(loop0): Failed to initialize $Extend.
=====================================
WARNING: bad unlock balance detected!
syzkaller #0 Not tainted
-------------------------------------
syz-executor416/5625 is trying to release lock (&ni->ni_lock) at:
[<ffffffff833dfc48>] ni_unlock fs/ntfs3/ntfs_fs.h:1266 [inline]
[<ffffffff833dfc48>] ntfs_readdir+0xac8/0xf00 fs/ntfs3/dir.c:625
but there are no more locks to release!

other info that might help us debug this:
locks held by syz-executor416/5625: 2, last CPU#0:
 #0: ffff8880741d62b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x118/0x160 fs/file.c:1409
 #1: ffff888076ed7490 (&type->i_mutex_dir_key#6){.+.+}-{4:4}, at: iterate_dir+0x287/0x880 fs/readdir.c:106

stack backtrace:
CPU: 0 UID: 0 PID: 5625 Comm: syz-executor416 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_unlock_imbalance_bug+0xdc/0xf0 kernel/locking/lockdep.c:5349
 __lock_release kernel/locking/lockdep.c:5590 [inline]
 lock_release+0x252/0x3c0 kernel/locking/lockdep.c:5964
 __mutex_unlock_slowpath+0x88/0x900 kernel/locking/mutex.c:989
 ni_unlock fs/ntfs3/ntfs_fs.h:1266 [inline]
 ntfs_readdir+0xac8/0xf00 fs/ntfs3/dir.c:625
 iterate_dir+0x3db/0x880 fs/readdir.c:114
 __do_sys_getdents fs/readdir.c:324 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:309
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3fff35c289
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 00 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 73 01 c3 48 c7 c1 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe78a3d2c8 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f3fff35c289
RDX: 00000000000000b8 RSI: 0000200000000040 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffe78a3d3f8
R10: 00007f3fff3acfb3 R11: 0000000000000246 R12: 00007ffe78a3d3e8
R13: 0000000000000002 R14: 00007f3fff404c80 R15: 000000000000000


---
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