======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.8.2982/19430 is trying to acquire lock:
ffff88807b0ad900 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0xb0/0x130 mm/memory.c:7174

but task is already holding lock:
ffff88806d732cb0 (&ni->ni_lock#2/5){+.+.}-{4:4}, at: ni_lock fs/ntfs3/ntfs_fs.h:1127 [inline]
ffff88806d732cb0 (&ni->ni_lock#2/5){+.+.}-{4:4}, at: ntfs_fiemap+0x10a/0x1a0 fs/ntfs3/file.c:1417

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ni->ni_lock#2/5){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:614 [inline]
       __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776
       ni_lock fs/ntfs3/ntfs_fs.h:1127 [inline]
       attr_data_get_block+0x2ec/0x1ec0 fs/ntfs3/attrib.c:918
       ntfs_file_mmap_prepare+0x53f/0x850 fs/ntfs3/file.c:393
       vfs_mmap_prepare include/linux/fs.h:2058 [inline]
       call_mmap_prepare mm/vma.c:2596 [inline]
       __mmap_region mm/vma.c:2692 [inline]
       mmap_region+0xb2b/0x1d10 mm/vma.c:2786
       do_mmap+0xc45/0x10d0 mm/mmap.c:558
       vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:581
       ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&mm->mmap_lock){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       __might_fault+0xcc/0x130 mm/memory.c:7174
       _inline_copy_to_user include/linux/uaccess.h:201 [inline]
       _copy_to_user+0x2c/0xb0 lib/usercopy.c:26
       copy_to_user include/linux/uaccess.h:236 [inline]
       fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:144
       ni_fiemap+0x89c/0xbf0 fs/ntfs3/frecord.c:2009
       ntfs_fiemap+0x11d/0x1a0 fs/ntfs3/file.c:1419
       ioctl_fiemap fs/ioctl.c:219 [inline]
       do_vfs_ioctl+0x1173/0x1430 fs/ioctl.c:531
       __do_sys_ioctl fs/ioctl.c:595 [inline]
       __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 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->ni_lock#2/5);
                               lock(&mm->mmap_lock);
                               lock(&ni->ni_lock#2/5);
  rlock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz.8.2982/19430:
 #0: ffff88806d732cb0 (&ni->ni_lock#2/5){+.+.}-{4:4}, at: ni_lock fs/ntfs3/ntfs_fs.h:1127 [inline]
 #0: ffff88806d732cb0 (&ni->ni_lock#2/5){+.+.}-{4:4}, at: ntfs_fiemap+0x10a/0x1a0 fs/ntfs3/file.c:1417

stack backtrace:
CPU: 0 UID: 0 PID: 19430 Comm: syz.8.2982 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 __might_fault+0xcc/0x130 mm/memory.c:7174
 _inline_copy_to_user include/linux/uaccess.h:201 [inline]
 _copy_to_user+0x2c/0xb0 lib/usercopy.c:26
 copy_to_user include/linux/uaccess.h:236 [inline]
 fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:144
 ni_fiemap+0x89c/0xbf0 fs/ntfs3/frecord.c:2009
 ntfs_fiemap+0x11d/0x1a0 fs/ntfs3/file.c:1419
 ioctl_fiemap fs/ioctl.c:219 [inline]
 do_vfs_ioctl+0x1173/0x1430 fs/ioctl.c:531
 __do_sys_ioctl fs/ioctl.c:595 [inline]
 __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ee698f749
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:00007f8ee7743038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8ee6be5fa0 RCX: 00007f8ee698f749
RDX: 0000200000000200 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f8ee6a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8ee6be6038 R14: 00007f8ee6be5fa0 R15: 00007fff5f8a1648
 </TASK>