syzbot

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc5-next-20250711-syzkaller #0 Not tainted
------------------------------------------------------
syz.5.686/10284 is trying to acquire lock:
ffff888053372fa8 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
ffff888053372fa8 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}, at: ntfs_file_mmap_prepare+0x599/0x770 fs/ntfs3/file.c:314

but task is already holding lock:
ffff8880212eefe0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:385 [inline]
ffff8880212eefe0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:577

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       gup_fast_fallback+0x238/0x2010 mm/gup.c:3216
       iov_iter_extract_user_pages lib/iov_iter.c:1846 [inline]
       iov_iter_extract_pages+0x35a/0x5e0 lib/iov_iter.c:1909
       dio_refill_pages fs/direct-io.c:172 [inline]
       dio_get_page fs/direct-io.c:213 [inline]
       do_direct_IO fs/direct-io.c:915 [inline]
       __blockdev_direct_IO+0x1166/0x3490 fs/direct-io.c:1243
       blockdev_direct_IO include/linux/fs.h:3503 [inline]
       ntfs_direct_IO+0x20b/0x410 fs/ntfs3/inode.c:813
       generic_file_direct_write+0x1db/0x3e0 mm/filemap.c:4109
       __generic_file_write_iter+0x11d/0x230 mm/filemap.c:4278
       ntfs_file_write_iter+0x71c/0x820 fs/ntfs3/file.c:1198
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x548/0xa90 fs/read_write.c:686
       ksys_write+0x145/0x250 fs/read_write.c:738
       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 (&sb->s_type->i_mutex_key#26){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       down_write+0x96/0x1f0 kernel/locking/rwsem.c:1592
       inode_lock include/linux/fs.h:869 [inline]
       ntfs_file_mmap_prepare+0x599/0x770 fs/ntfs3/file.c:314
       vfs_mmap_prepare include/linux/fs.h:2294 [inline]
       call_mmap_prepare mm/vma.c:2587 [inline]
       __mmap_region mm/vma.c:2655 [inline]
       mmap_region+0xb41/0x20c0 mm/vma.c:2741
       do_mmap+0xc45/0x10d0 mm/mmap.c:561
       vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:579
       ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:607
       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(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#26);
                               lock(&mm->mmap_lock);
  lock(&sb->s_type->i_mutex_key#26);

 *** DEADLOCK ***

1 lock held by syz.5.686/10284:
 #0: ffff8880212eefe0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:385 [inline]
 #0: ffff8880212eefe0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:577

stack backtrace:
CPU: 1 UID: 0 PID: 10284 Comm: syz.5.686 Not tainted 6.16.0-rc5-next-20250711-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1592
 inode_lock include/linux/fs.h:869 [inline]
 ntfs_file_mmap_prepare+0x599/0x770 fs/ntfs3/file.c:314
 vfs_mmap_prepare include/linux/fs.h:2294 [inline]
 call_mmap_prepare mm/vma.c:2587 [inline]
 __mmap_region mm/vma.c:2655 [inline]
 mmap_region+0xb41/0x20c0 mm/vma.c:2741
 do_mmap+0xc45/0x10d0 mm/mmap.c:561
 vm_mmap_pgoff+0x2a6/0x4d0 mm/util.c:579
 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:607
 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: 0033:0x7f5f1d98e929
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:00007f5f1e801038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f5f1dbb6080 RCX: 00007f5f1d98e929
RDX: 00000000027ffff7 RSI: 0000000000004000 RDI: 0000200000ffb000
RBP: 00007f5f1da10b39 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5f1dbb6080 R15: 00007fff1b838578
 </TASK>