============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.66/6309 is trying to acquire lock:
ffff88817435c0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300

but task is already holding lock:
ffff88817435c0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300

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

6 locks held by syz.0.66/6309:
 #0: ffff88816847b8f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff8881756be420 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x227/0xb90
 #2: ffff8881ace436a0 (&sb->s_type->i_mutex_key#38){+.+.}-{4:4}, at: generic_file_write_iter+0x11e/0x680
 #3: ffff8881ace434f8 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0
 #4: ffff88817435c0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300
 #5: ffff8881ace44878 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0

stack backtrace:
CPU: 1 UID: 0 PID: 6309 Comm: syz.0.66 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_deadlock_bug+0x279/0x290
 __lock_acquire+0x253f/0x2cf0
 lock_acquire+0xf0/0x2e0
 __mutex_lock+0x19f/0x1300
 hfs_find_init+0x18e/0x300
 hfs_extend_file+0x35c/0x15e0
 hfs_bmap_reserve+0x107/0x430
 __hfs_ext_write_extent+0x1fa/0x470
 __hfs_ext_cache_extent+0x6b/0x9b0
 hfs_extend_file+0x39b/0x15e0
 hfs_get_block+0x412/0xc50
 __block_write_begin_int+0x6c6/0x1910
 cont_write_begin+0x737/0xae0
 hfs_write_begin+0x66/0xb0
 generic_perform_write+0x2e2/0x8f0
 generic_file_write_iter+0x14a/0x680
 vfs_write+0x61d/0xb90
 ksys_write+0x150/0x270
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba8879c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fba89670028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fba88a15fa0 RCX: 00007fba8879c799
RDX: 00000000ffffff20 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fba88832bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fba88a16038 R14: 00007fba88a15fa0 R15: 00007fff5ea019d8
 </TASK>
