syzbot

loop0: detected capacity change from 0 to 4096
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.19/6051 is trying to acquire lock:
ffff8880351b2250 (&wnd->rw_lock){++++}-{4:4}, at: mark_as_free_ex+0x3e/0x390 fs/ntfs3/fsntfs.c:2464

but task is already holding lock:
ffff8880487fbf90 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_truncate fs/ntfs3/file.c:455 [inline]
ffff8880487fbf90 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_setattr+0x70e/0xbe0 fs/ntfs3/file.c:778

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->file.run_lock#2){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       down_read+0x97/0x1f0 kernel/locking/rwsem.c:1537
       run_unpack_ex+0x7e5/0xba0 fs/ntfs3/run.c:1119
       ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
       ntfs_iget5+0x232b/0x37c0 fs/ntfs3/inode.c:540
       dir_search_u+0x1df/0x2c0 fs/ntfs3/dir.c:264
       ntfs_lookup+0xfb/0x1f0 fs/ntfs3/namei.c:85
       lookup_open fs/namei.c:3686 [inline]
       open_last_lookups fs/namei.c:3807 [inline]
       path_openat+0x110d/0x3840 fs/namei.c:4043
       do_filp_open+0x1fa/0x410 fs/namei.c:4073
       do_sys_openat2+0x121/0x1c0 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_creat fs/open.c:1528 [inline]
       __se_sys_creat fs/open.c:1522 [inline]
       __x64_sys_creat+0x8f/0xc0 fs/open.c:1522
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&wnd->rw_lock){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
       down_write_nested+0x3e/0x60 kernel/locking/rwsem.c:1706
       mark_as_free_ex+0x3e/0x390 fs/ntfs3/fsntfs.c:2464
       run_deallocate_ex+0x187/0x2f0 fs/ntfs3/attrib.c:122
       attr_set_size+0xeb9/0x2c70 fs/ntfs3/attrib.c:753
       ntfs_truncate fs/ntfs3/file.c:456 [inline]
       ntfs_setattr+0x7d0/0xbe0 fs/ntfs3/file.c:778
       notify_change+0xb31/0xe60 fs/attr.c:552
       do_truncate+0x1a4/0x220 fs/open.c:68
       handle_truncate fs/namei.c:3508 [inline]
       do_open fs/namei.c:3891 [inline]
       path_openat+0x3078/0x3840 fs/namei.c:4046
       do_filp_open+0x1fa/0x410 fs/namei.c:4073
       do_sys_openat2+0x121/0x1c0 fs/open.c:1435
       do_sys_open fs/open.c:1450 [inline]
       __do_sys_creat fs/open.c:1528 [inline]
       __se_sys_creat fs/open.c:1522 [inline]
       __x64_sys_creat+0x8f/0xc0 fs/open.c:1522
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ni->file.run_lock#2);
                               lock(&wnd->rw_lock);
                               lock(&ni->file.run_lock#2);
  lock(&wnd->rw_lock);

 *** DEADLOCK ***

4 locks held by syz.0.19/6051:
 #0: ffff8880351b4488 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff8880487fc1a8 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:874 [inline]
 #1: ffff8880487fc1a8 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: do_truncate+0x171/0x220 fs/open.c:63
 #2: ffff8880487fbef0 (&ni->ni_lock/5){+.+.}-{4:4}, at: ni_lock fs/ntfs3/ntfs_fs.h:1113 [inline]
 #2: ffff8880487fbef0 (&ni->ni_lock/5){+.+.}-{4:4}, at: ntfs_truncate fs/ntfs3/file.c:453 [inline]
 #2: ffff8880487fbef0 (&ni->ni_lock/5){+.+.}-{4:4}, at: ntfs_setattr+0x6fd/0xbe0 fs/ntfs3/file.c:778
 #3: ffff8880487fbf90 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_truncate fs/ntfs3/file.c:455 [inline]
 #3: ffff8880487fbf90 (&ni->file.run_lock#2){++++}-{4:4}, at: ntfs_setattr+0x70e/0xbe0 fs/ntfs3/file.c:778

stack backtrace:
CPU: 1 UID: 0 PID: 6051 Comm: syz.0.19 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 down_write_nested+0x3e/0x60 kernel/locking/rwsem.c:1706
 mark_as_free_ex+0x3e/0x390 fs/ntfs3/fsntfs.c:2464
 run_deallocate_ex+0x187/0x2f0 fs/ntfs3/attrib.c:122
 attr_set_size+0xeb9/0x2c70 fs/ntfs3/attrib.c:753
 ntfs_truncate fs/ntfs3/file.c:456 [inline]
 ntfs_setattr+0x7d0/0xbe0 fs/ntfs3/file.c:778
 notify_change+0xb31/0xe60 fs/attr.c:552
 do_truncate+0x1a4/0x220 fs/open.c:68
 handle_truncate fs/namei.c:3508 [inline]
 do_open fs/namei.c:3891 [inline]
 path_openat+0x3078/0x3840 fs/namei.c:4046
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_creat fs/open.c:1528 [inline]
 __se_sys_creat fs/open.c:1522 [inline]
 __x64_sys_creat+0x8f/0xc0 fs/open.c:1522
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff4d8bdebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef3e4a208 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007ff4d8e05fa0 RCX: 00007ff4d8bdebe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007ff4d8c61e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4d8e05fa0 R14: 00007ff4d8e05fa0 R15: 0000000000000002
 </TASK>