syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.146-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.86/4723 is trying to acquire lock:
ffff8880698cb740 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
ffff8880698cb740 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: ntfs_file_mmap+0x4de/0x6a0 fs/ntfs3/file.c:320

but task is already holding lock:
ffff88807dbf6a58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff88807dbf6a58 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:518

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
       internal_get_user_pages_fast+0x1fa/0x2620 mm/gup.c:3042
       __iov_iter_get_pages_alloc+0x3b7/0xb40 lib/iov_iter.c:1460
       iov_iter_get_pages2+0x5b/0x90 lib/iov_iter.c:1503
       dio_refill_pages fs/direct-io.c:172 [inline]
       dio_get_page fs/direct-io.c:215 [inline]
       do_direct_IO fs/direct-io.c:932 [inline]
       __blockdev_direct_IO+0x1097/0x3450 fs/direct-io.c:1266
       blockdev_direct_IO include/linux/fs.h:3342 [inline]
       ntfs_direct_IO+0x194/0x390 fs/ntfs3/inode.c:798
       generic_file_direct_write+0x3be/0x660 mm/filemap.c:3770
       __generic_file_write_iter+0x1db/0x430 mm/filemap.c:3930
       ntfs_file_write_iter+0x618/0x6f0 fs/ntfs3/file.c:1081
       do_iter_readv_writev fs/read_write.c:-1 [inline]
       do_iter_write+0x62d/0xaf0 fs/read_write.c:861
       vfs_writev fs/read_write.c:934 [inline]
       do_writev+0x24e/0x410 fs/read_write.c:977
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       ntfs_file_mmap+0x4de/0x6a0 fs/ntfs3/file.c:320
       call_mmap include/linux/fs.h:2270 [inline]
       mmap_file+0x5d/0xb0 mm/util.c:1109
       __mmap_region mm/mmap.c:2768 [inline]
       mmap_region+0xf78/0x1d30 mm/mmap.c:2912
       do_mmap+0x894/0xf30 mm/mmap.c:1432
       vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
       ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1478
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 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(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#21);
                               lock(&mm->mmap_lock);
  lock(&sb->s_type->i_mutex_key#21);

 *** DEADLOCK ***

1 lock held by syz.4.86/4723:
 #0: ffff88807dbf6a58 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff88807dbf6a58 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0x15d/0x2b0 mm/util.c:518

stack backtrace:
CPU: 1 PID: 4723 Comm: syz.4.86 Not tainted 6.1.146-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 down_write+0x36/0x60 kernel/locking/rwsem.c:1573
 inode_lock include/linux/fs.h:758 [inline]
 ntfs_file_mmap+0x4de/0x6a0 fs/ntfs3/file.c:320
 call_mmap include/linux/fs.h:2270 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1109
 __mmap_region mm/mmap.c:2768 [inline]
 mmap_region+0xf78/0x1d30 mm/mmap.c:2912
 do_mmap+0x894/0xf30 mm/mmap.c:1432
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1478
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9bfc78e9a9
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:00007f9bfd5bd038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f9bfc9b6080 RCX: 00007f9bfc78e9a9
RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f9bfc810d69 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f9bfc9b6080 R15: 00007ffd7eb62c08
 </TASK>