======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.494/8604 is trying to acquire lock:
ffff88816f6dc0a8 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18d/0x300

but task is already holding lock:
ffff8881be4d00a0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf9/0x1680

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       hfs_extend_file+0xf9/0x1680
       hfs_bmap_reserve+0x108/0x430
       __hfs_ext_write_extent+0x1fc/0x470
       __hfs_ext_cache_extent+0x6e/0x9b0
       hfs_extend_file+0x3a0/0x1680
       hfs_get_block+0x401/0xbe0
       __block_write_begin_int+0x6c2/0x1900
       cont_write_begin+0x71b/0xac0
       hfs_write_begin+0x66/0xb0
       cont_write_begin+0x2d6/0xac0
       hfs_write_begin+0x66/0xb0
       hfs_file_truncate+0x1cf/0xb60
       hfs_inode_setattr+0x49a/0x6c0
       notify_change+0xbba/0xea0
       do_truncate+0x1c2/0x250
       do_ftruncate+0x4d4/0x580
       __x64_sys_ftruncate+0x8f/0xe0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&tree->tree_lock/1){+.+.}-{4:4}:
       __lock_acquire+0x1520/0x2cf0
       lock_acquire+0x106/0x350
       __mutex_lock+0x19d/0x1550
       hfs_find_init+0x18d/0x300
       hfs_extend_file+0x35f/0x1680
       hfs_bmap_reserve+0x108/0x430
       hfs_cat_create+0x221/0x810
       hfs_mkdir+0x79/0xe0
       vfs_mkdir+0x406/0x620
       filename_mkdirat+0x285/0x510
       __se_sys_mkdirat+0x35/0x150
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
  lock(&tree->tree_lock/1);

 *** DEADLOCK ***

4 locks held by syz.1.494/8604:
 #0: ffff88816a0fe450 (sb_writers#23){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff8881be4d5040 (&type->i_mutex_dir_key#15/1){+.+.}-{4:4}, at: filename_create+0x200/0x370
 #2: ffff88816f6da0a8 (&tree->tree_lock){+.+.}-{4:4}, at: hfs_find_init+0x18d/0x300
 #3: ffff8881be4d00a0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf9/0x1680

stack backtrace:
CPU: 1 UID: 0 PID: 8604 Comm: syz.1.494 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_circular_bug+0x2e1/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x1520/0x2cf0
 lock_acquire+0x106/0x350
 __mutex_lock+0x19d/0x1550
 hfs_find_init+0x18d/0x300
 hfs_extend_file+0x35f/0x1680
 hfs_bmap_reserve+0x108/0x430
 hfs_cat_create+0x221/0x810
 hfs_mkdir+0x79/0xe0
 vfs_mkdir+0x406/0x620
 filename_mkdirat+0x285/0x510
 __se_sys_mkdirat+0x35/0x150
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f97e7d9bcc7
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f97e8cece58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f97e8cecee0 RCX: 00007f97e7d9bcc7
RDX: 00000000000001ff RSI: 0000200000000180 RDI: 00000000ffffff9c
RBP: 0000200000000140 R08: 0000200000000080 R09: 0000000000000000
R10: 0000200000000140 R11: 0000000000000246 R12: 0000200000000180
R13: 00007f97e8cecea0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
