======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.1704/20022 is trying to acquire lock:
ffff8881bbf8c870 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0

but task is already holding lock:
ffff88810eb6e0a8 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{4:4}:
       __mutex_lock+0x1a3/0x1550
       hfs_find_init+0x18e/0x300
       hfs_extend_file+0x35c/0x15e0
       hfs_bmap_reserve+0x107/0x430
       hfs_cat_create+0x20f/0x800
       hfs_mkdir+0x79/0xe0
       vfs_mkdir+0x413/0x630
       filename_mkdirat+0x285/0x510
       __se_sys_mkdirat+0x35/0x150
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       __lock_acquire+0x15a5/0x2cf0
       lock_acquire+0x106/0x350
       __mutex_lock+0x1a3/0x1550
       hfs_extend_file+0xf2/0x15e0
       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
       cont_write_begin+0x2e7/0xae0
       hfs_write_begin+0x66/0xb0
       hfs_file_truncate+0x1cf/0xb70
       hfs_inode_setattr+0x4a9/0x670
       notify_change+0xc1a/0xf40
       do_truncate+0x1c2/0x250
       vfs_truncate+0x4b4/0x540
       ksys_truncate+0xf3/0x1c0
       __x64_sys_truncate+0x5b/0x70
       do_syscall_64+0x15f/0xf80
       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/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

4 locks held by syz.0.1704/20022:
 #0: ffff88810c9c6410 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff8881bbf8b690 (&sb->s_type->i_mutex_key#24){++++}-{4:4}, at: do_truncate+0x18f/0x250
 #2: ffff8881bbf8b4f0 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0
 #3: ffff88810eb6e0a8 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300

stack backtrace:
CPU: 0 UID: 0 PID: 20022 Comm: syz.0.1704 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+0x15a5/0x2cf0
 lock_acquire+0x106/0x350
 __mutex_lock+0x1a3/0x1550
 hfs_extend_file+0xf2/0x15e0
 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
 cont_write_begin+0x2e7/0xae0
 hfs_write_begin+0x66/0xb0
 hfs_file_truncate+0x1cf/0xb70
 hfs_inode_setattr+0x4a9/0x670
 notify_change+0xc1a/0xf40
 do_truncate+0x1c2/0x250
 vfs_truncate+0x4b4/0x540
 ksys_truncate+0xf3/0x1c0
 __x64_sys_truncate+0x5b/0x70
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7e8b19cdd9
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:00007f7e8c0ab028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f7e8b415fa0 RCX: 00007f7e8b19cdd9
RDX: 0000000000000000 RSI: 0000000002fffffd RDI: 0000200000000940
RBP: 00007f7e8b232d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7e8b416038 R14: 00007f7e8b415fa0 R15: 00007ffe0480deb8
 </TASK>
