loop2: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.1007/9470 is trying to acquire lock:
ffff888116e41af8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x1550

but task is already holding lock:
ffff88811d60a0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x2c0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock#2/1){+.+.}-{4:4}:
       lock_acquire+0x11f/0x350
       __mutex_lock+0x19f/0x1300
       hfs_find_init+0x18e/0x2c0
       hfs_extend_file+0x35c/0x1550
       hfs_bmap_reserve+0x107/0x430
       hfs_cat_create+0x20f/0x7c0
       hfs_mkdir+0x6c/0xe0
       vfs_mkdir+0x306/0x510
       do_mkdirat+0x24f/0x5a0
       __x64_sys_mkdirat+0x87/0xa0
       do_syscall_64+0xf0/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       validate_chain+0xb9a/0x2130
       __lock_acquire+0xab8/0xd20
       lock_acquire+0x11f/0x350
       __mutex_lock+0x19f/0x1300
       hfs_extend_file+0xf2/0x1550
       hfs_bmap_reserve+0x107/0x430
       __hfs_ext_write_extent+0x1fa/0x470
       hfs_ext_write_extent+0x17e/0x210
       hfs_write_inode+0x117/0x960
       __writeback_single_inode+0x6f1/0xfe0
       writeback_single_inode+0x1f9/0x6a0
       write_inode_now+0x1c2/0x290
       hfs_file_fsync+0xa4/0x140
       generic_file_write_iter+0x37e/0x680
       vfs_write+0x61d/0xb90
       ksys_write+0x150/0x270
       do_syscall_64+0xf0/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tree->tree_lock#2/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock#2/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

4 locks held by syz.2.1007/9470:
 #0: ffff8881a7fabcf8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x246/0x320
 #1: ffff888115416420 (sb_writers#19){.+.+}-{0:0}, at: vfs_write+0x227/0xb90
 #2: ffff888116e429a0 (&sb->s_type->i_mutex_key#25){+.+.}-{4:4}, at: hfs_file_fsync+0x9a/0x140
 #3: ffff88811d60a0b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x2c0

stack backtrace:
CPU: 0 UID: 0 PID: 9470 Comm: syz.2.1007 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+0x1a9/0x280
 print_circular_bug+0x2ed/0x300
 check_noncircular+0x134/0x160
 validate_chain+0xb9a/0x2130
 __lock_acquire+0xab8/0xd20
 lock_acquire+0x11f/0x350
 __mutex_lock+0x19f/0x1300
 hfs_extend_file+0xf2/0x1550
 hfs_bmap_reserve+0x107/0x430
 __hfs_ext_write_extent+0x1fa/0x470
 hfs_ext_write_extent+0x17e/0x210
 hfs_write_inode+0x117/0x960
 __writeback_single_inode+0x6f1/0xfe0
 writeback_single_inode+0x1f9/0x6a0
 write_inode_now+0x1c2/0x290
 hfs_file_fsync+0xa4/0x140
 generic_file_write_iter+0x37e/0x680
 vfs_write+0x61d/0xb90
 ksys_write+0x150/0x270
 do_syscall_64+0xf0/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24b019acb9
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:00007f24b1054028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f24b0415fa0 RCX: 00007f24b019acb9
RDX: 0000000000001006 RSI: 0000200000001980 RDI: 0000000000000004
RBP: 00007f24b0208bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f24b0416038 R14: 00007f24b0415fa0 R15: 00007fff22fcc2f8
 </TASK>
