syzbot

loop0: detected capacity change from 0 to 4096
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.68/5991 is trying to acquire lock:
ffff88802fa7e270 (&wnd->rw_lock){++++}-{3:3}, at: mark_as_free_ex+0x3e/0x380 fs/ntfs3/fsntfs.c:2484

but task is already holding lock:
ffff888072a68910 (&ni->file.run_lock#2){++++}-{3:3}, at: ntfs_truncate fs/ntfs3/file.c:396 [inline]
ffff888072a68910 (&ni->file.run_lock#2){++++}-{3:3}, at: ntfs3_setattr+0x6cd/0xb60 fs/ntfs3/file.c:706

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->file.run_lock#2){++++}-{3:3}:
       down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
       run_unpack_ex+0x7e6/0xba0 fs/ntfs3/run.c:1122
       ntfs_read_mft fs/ntfs3/inode.c:401 [inline]
       ntfs_iget5+0x22e3/0x3750 fs/ntfs3/inode.c:533
       ntfs_dir_emit fs/ntfs3/dir.c:338 [inline]
       ntfs_read_hdr+0x7d4/0xc30 fs/ntfs3/dir.c:386
       ntfs_readdir+0xaf4/0xe60 fs/ntfs3/dir.c:497
       iterate_dir+0x1c2/0x580 fs/readdir.c:106
       __do_sys_getdents64 fs/readdir.c:405 [inline]
       __se_sys_getdents64+0xe9/0x260 fs/readdir.c:390
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&wnd->rw_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3869 [inline]
       __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
       lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
       down_write_nested+0x9e/0x1f0 kernel/locking/rwsem.c:1689
       mark_as_free_ex+0x3e/0x380 fs/ntfs3/fsntfs.c:2484
       run_deallocate_ex+0x188/0x2e0 fs/ntfs3/attrib.c:122
       attr_set_size+0xeb5/0x2c60 fs/ntfs3/attrib.c:754
       ntfs_truncate fs/ntfs3/file.c:397 [inline]
       ntfs3_setattr+0x78f/0xb60 fs/ntfs3/file.c:706
       notify_change+0xb0d/0xe10 fs/attr.c:499
       do_truncate+0x19b/0x220 fs/open.c:66
       vfs_truncate+0x266/0x300 fs/open.c:112
       do_sys_truncate+0xe0/0x1a0 fs/open.c:135
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

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.0.68/5991:
 #0: ffff888024e00418 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:412
 #1: ffff888072a68b10 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #1: ffff888072a68b10 (&sb->s_type->i_mutex_key#20){+.+.}-{3:3}, at: do_truncate+0x187/0x220 fs/open.c:64
 #2: ffff888072a68860 (&ni->ni_lock#2/5){+.+.}-{3:3}, at: ni_lock fs/ntfs3/ntfs_fs.h:1119 [inline]
 #2: ffff888072a68860 (&ni->ni_lock#2/5){+.+.}-{3:3}, at: ntfs_truncate fs/ntfs3/file.c:394 [inline]
 #2: ffff888072a68860 (&ni->ni_lock#2/5){+.+.}-{3:3}, at: ntfs3_setattr+0x6bc/0xb60 fs/ntfs3/file.c:706
 #3: ffff888072a68910 (&ni->file.run_lock#2){++++}-{3:3}, at: ntfs_truncate fs/ntfs3/file.c:396 [inline]
 #3: ffff888072a68910 (&ni->file.run_lock#2){++++}-{3:3}, at: ntfs3_setattr+0x6cd/0xb60 fs/ntfs3/file.c:706

stack backtrace:
CPU: 0 PID: 5991 Comm: syz.0.68 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3869 [inline]
 __lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 down_write_nested+0x9e/0x1f0 kernel/locking/rwsem.c:1689
 mark_as_free_ex+0x3e/0x380 fs/ntfs3/fsntfs.c:2484
 run_deallocate_ex+0x188/0x2e0 fs/ntfs3/attrib.c:122
 attr_set_size+0xeb5/0x2c60 fs/ntfs3/attrib.c:754
 ntfs_truncate fs/ntfs3/file.c:397 [inline]
 ntfs3_setattr+0x78f/0xb60 fs/ntfs3/file.c:706
 notify_change+0xb0d/0xe10 fs/attr.c:499
 do_truncate+0x19b/0x220 fs/open.c:66
 vfs_truncate+0x266/0x300 fs/open.c:112
 do_sys_truncate+0xe0/0x1a0 fs/open.c:135
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f756958f6c9
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:00007ffe4ba67a68 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f75697e5fa0 RCX: 00007f756958f6c9
RDX: 0000000000000000 RSI: 000000000001bf00 RDI: 00002000000000c0
RBP: 00007f7569611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75697e5fa0 R14: 00007f75697e5fa0 R15: 0000000000000002
 </TASK>