============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.394/8843 is trying to acquire lock:
ffff88810d2520b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x184/0x200

but task is already holding lock:
ffff88810d2520b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x184/0x200

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&tree->tree_lock#2/1);
  lock(&tree->tree_lock#2/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz.1.394/8843:
 #0: ffff888119190428 (sb_writers#32){.+.+}-{0:0}, at: do_ftruncate+0x42a/0x540
 #1: ffff88803cdf1ca0 (&sb->s_type->i_mutex_key#42){+.+.}-{4:4}, at: do_truncate+0x171/0x220
 #2: ffff88803cdf1af8 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1230
 #3: ffff88810d2520b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x184/0x200
 #4: ffff88811dc61af8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1230

stack backtrace:
CPU: 1 UID: 0 PID: 8843 Comm: syz.1.394 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+0x189/0x250
 print_deadlock_bug+0x28b/0x2a0
 validate_chain+0x1a3f/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x187/0x1350
 hfs_find_init+0x184/0x200
 hfs_extend_file+0x2ee/0x1230
 hfs_bmap_reserve+0x107/0x430
 __hfs_ext_write_extent+0x1fa/0x470
 __hfs_ext_cache_extent+0x6b/0x9b0
 hfs_extend_file+0x316/0x1230
 hfs_get_block+0x3d7/0xbd0
 __block_write_begin_int+0x6b5/0x1900
 cont_write_begin+0x789/0xb50
 hfs_write_begin+0x66/0xb0
 cont_write_begin+0x2fd/0xb50
 hfs_write_begin+0x66/0xb0
 hfs_file_truncate+0x190/0x9c0
 hfs_inode_setattr+0x4a9/0x670
 notify_change+0xb36/0xe40
 do_truncate+0x1a4/0x220
 do_ftruncate+0x489/0x540
 __x64_sys_ftruncate+0x92/0xf0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3bf478ebe9
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:00007f3bf559c038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f3bf49c5fa0 RCX: 00007f3bf478ebe9
RDX: 0000000000000000 RSI: 0000000002000009 RDI: 0000000000000004
RBP: 00007f3bf4811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3bf49c6038 R14: 00007f3bf49c5fa0 R15: 00007ffcb9ce6ae8
 </TASK>
