======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u10:6/14448 is trying to acquire lock:
ffff88811c84b4f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1230

but task is already holding lock:
ffff888119dc80b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x184/0x200

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{4:4}:
       lock_acquire+0x120/0x360
       __mutex_lock+0x187/0x1350
       hfs_find_init+0x184/0x200
       hfs_extend_file+0x2ee/0x1230
       hfs_bmap_reserve+0x107/0x430
       hfs_cat_create+0x1b3/0x640
       hfs_mkdir+0x6c/0xe0
       vfs_mkdir+0x306/0x510
       do_mkdirat+0x247/0x590
       __x64_sys_mkdirat+0x87/0xa0
       do_syscall_64+0xfa/0x3b0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       validate_chain+0xb9b/0x2140
       __lock_acquire+0xab9/0xd20
       lock_acquire+0x120/0x360
       __mutex_lock+0x187/0x1350
       hfs_extend_file+0xda/0x1230
       hfs_bmap_reserve+0x107/0x430
       __hfs_ext_write_extent+0x1fa/0x470
       hfs_ext_write_extent+0x161/0x1e0
       hfs_write_inode+0x91/0x7d0
       __writeback_single_inode+0x6f1/0xff0
       writeback_sb_inodes+0x6c7/0x1010
       wb_writeback+0x43b/0xaf0
       wb_workfn+0x409/0xef0
       process_scheduled_works+0xae1/0x17b0
       worker_thread+0x8a0/0xda0
       kthread+0x711/0x8a0
       ret_from_fork+0x3fc/0x770
       ret_from_fork_asm+0x1a/0x30

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 ***

3 locks held by kworker/u10:6/14448:
 #0: ffff88801b307148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90002e77bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888119dc80b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x184/0x200

stack backtrace:
CPU: 1 UID: 0 PID: 14448 Comm: kworker/u10:6 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
Workqueue: writeback wb_workfn (flush-7:8)
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_circular_bug+0x2ee/0x310
 check_noncircular+0x134/0x160
 validate_chain+0xb9b/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x187/0x1350
 hfs_extend_file+0xda/0x1230
 hfs_bmap_reserve+0x107/0x430
 __hfs_ext_write_extent+0x1fa/0x470
 hfs_ext_write_extent+0x161/0x1e0
 hfs_write_inode+0x91/0x7d0
 __writeback_single_inode+0x6f1/0xff0
 writeback_sb_inodes+0x6c7/0x1010
 wb_writeback+0x43b/0xaf0
 wb_workfn+0x409/0xef0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
hfs: new node 0 already hashed?
------------[ cut here ]------------
WARNING: CPU: 1 PID: 14448 at fs/hfs/bnode.c:520 hfs_bnode_create+0x461/0x4f0
Modules linked in:
CPU: 1 UID: 0 PID: 14448 Comm: kworker/u10:6 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
Workqueue: writeback wb_workfn (flush-7:8)
RIP: 0010:hfs_bnode_create+0x461/0x4f0
Code: a1 8b 89 ee e8 60 d2 8d fe e9 cf fc ff ff e8 96 e1 25 ff 4c 89 ef e8 5e f0 e2 08 48 c7 c7 a0 ce a1 8b 89 ee e8 40 d2 8d fe 90 <0f> 0b 90 eb b0 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c d6 fb ff ff
RSP: 0018:ffffc90002e76c20 EFLAGS: 00010246
RAX: 000000000000001f RBX: ffff888119dc8000 RCX: 8ab145ab7d1f2e00
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1bfa1f4 R12: 0000000000000000
R13: ffff888119dc80e0 R14: ffff88803a1dfb00 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881a3c15000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555885c95c8 CR3: 000000000df36000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 hfs_bmap_alloc+0x5bb/0x640
 hfs_btree_inc_height+0xf6/0xac0
 hfs_brec_insert+0x743/0xbd0
 __hfs_ext_write_extent+0x2a1/0x470
 hfs_ext_write_extent+0x161/0x1e0
 hfs_write_inode+0x91/0x7d0
 __writeback_single_inode+0x6f1/0xff0
 writeback_sb_inodes+0x6c7/0x1010
 wb_writeback+0x43b/0xaf0
 wb_workfn+0x409/0xef0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
