syzbot

loop0: detected capacity change from 0 to 4096
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/6717 is trying to acquire lock:
ffff0000f1c67680 (&ni->ni_lock#3/5){+.+.}-{4:4}, at: ni_lock fs/ntfs3/ntfs_fs.h:1113 [inline]
ffff0000f1c67680 (&ni->ni_lock#3/5){+.+.}-{4:4}, at: attr_data_get_block+0x1e0/0x1864 fs/ntfs3/attrib.c:918

but task is already holding lock:
ffff0000d9a4de50 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline]
ffff0000d9a4de50 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1dc/0x45c mm/util.c:578

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{4:4}:
       __might_fault+0xc4/0x124 mm/memory.c:6958
       _inline_copy_to_user include/linux/uaccess.h:192 [inline]
       copy_to_user include/linux/uaccess.h:223 [inline]
       fiemap_fill_next_extent+0x17c/0x3f0 fs/ioctl.c:145
       ni_fiemap+0x2e8/0x9ec fs/ntfs3/frecord.c:1896
       ntfs_fiemap+0x10c/0x188 fs/ntfs3/file.c:1326
       ioctl_fiemap fs/ioctl.c:220 [inline]
       do_vfs_ioctl+0x1140/0x1834 fs/ioctl.c:532
       __do_sys_ioctl fs/ioctl.c:596 [inline]
       __se_sys_ioctl fs/ioctl.c:584 [inline]
       __arm64_sys_ioctl+0xe4/0x1c4 fs/ioctl.c:584
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

-> #0 (&ni->ni_lock#3/5){+.+.}-{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+0x1774/0x30a4 kernel/locking/lockdep.c:5237
       lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
       __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
       __mutex_lock kernel/locking/mutex.c:760 [inline]
       mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
       ni_lock fs/ntfs3/ntfs_fs.h:1113 [inline]
       attr_data_get_block+0x1e0/0x1864 fs/ntfs3/attrib.c:918
       ntfs_file_mmap_prepare+0x400/0x650 fs/ntfs3/file.c:318
       vfs_mmap_prepare include/linux/fs.h:2295 [inline]
       call_mmap_prepare mm/vma.c:2585 [inline]
       __mmap_region mm/vma.c:2653 [inline]
       mmap_region+0x934/0x1d20 mm/vma.c:2739
       do_mmap+0x968/0xfac mm/mmap.c:558
       vm_mmap_pgoff+0x2d8/0x45c mm/util.c:580
       ksys_mmap_pgoff+0x394/0x5b8 mm/mmap.c:604
       __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
       __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
       __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
       __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
       invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
       el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
       do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
       el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
       el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
       el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_lock);
                               lock(&ni->ni_lock#3/5);
                               lock(&mm->mmap_lock);
  lock(&ni->ni_lock#3/5);

 *** DEADLOCK ***

1 lock held by syz.0.17/6717:
 #0: ffff0000d9a4de50 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:415 [inline]
 #0: ffff0000d9a4de50 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1dc/0x45c mm/util.c:578

stack backtrace:
CPU: 1 UID: 0 PID: 6717 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 dump_stack+0x1c/0x28 lib/dump_stack.c:129
 print_circular_bug+0x324/0x32c kernel/locking/lockdep.c:2043
 check_noncircular+0x154/0x174 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+0x1774/0x30a4 kernel/locking/lockdep.c:5237
 lock_acquire+0x14c/0x2e0 kernel/locking/lockdep.c:5868
 __mutex_lock_common+0x1d0/0x2678 kernel/locking/mutex.c:598
 __mutex_lock kernel/locking/mutex.c:760 [inline]
 mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
 ni_lock fs/ntfs3/ntfs_fs.h:1113 [inline]
 attr_data_get_block+0x1e0/0x1864 fs/ntfs3/attrib.c:918
 ntfs_file_mmap_prepare+0x400/0x650 fs/ntfs3/file.c:318
 vfs_mmap_prepare include/linux/fs.h:2295 [inline]
 call_mmap_prepare mm/vma.c:2585 [inline]
 __mmap_region mm/vma.c:2653 [inline]
 mmap_region+0x934/0x1d20 mm/vma.c:2739
 do_mmap+0x968/0xfac mm/mmap.c:558
 vm_mmap_pgoff+0x2d8/0x45c mm/util.c:580
 ksys_mmap_pgoff+0x394/0x5b8 mm/mmap.c:604
 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
 __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
 __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596