======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u10:5/1092 is trying to acquire lock:
ffff888020be41f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0

but task is already holding lock:
ffff88801cd420b0 (&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+0x19f/0x1300
       hfs_find_init+0x18e/0x300
       hfs_extend_file+0x35c/0x15e0
       hfs_bmap_reserve+0x107/0x430
       hfs_cat_create+0x20f/0x800
       hfs_mkdir+0x6c/0xe0
       vfs_mkdir+0x511/0x5b0
       do_mkdirat+0x27d/0x4b0
       __x64_sys_mkdirat+0x87/0xa0
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       __lock_acquire+0x15a5/0x2cf0
       lock_acquire+0x106/0x330
       __mutex_lock+0x19f/0x1300
       hfs_extend_file+0xf2/0x15e0
       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+0x7e1/0x1230
       writeback_sb_inodes+0x92c/0x1820
       wb_writeback+0x445/0xad0
       wb_workfn+0x3f8/0xef0
       process_scheduled_works+0xaec/0x17a0
       worker_thread+0x89f/0xd90
       kthread+0x726/0x8b0
       ret_from_fork+0x51b/0xa40
       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/u10:5/1092:
 #0: ffff888162297948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0
 #1: ffffc9000812fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0
 #2: ffff88801cd420b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300

stack backtrace:
CPU: 1 UID: 0 PID: 1092 Comm: kworker/u10:5 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+0xe8/0x150
 print_circular_bug+0x2e1/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x15a5/0x2cf0
 lock_acquire+0x106/0x330
 __mutex_lock+0x19f/0x1300
 hfs_extend_file+0xf2/0x15e0
 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+0x7e1/0x1230
 writeback_sb_inodes+0x92c/0x1820
 wb_writeback+0x445/0xad0
 wb_workfn+0x3f8/0xef0
 process_scheduled_works+0xaec/0x17a0
 worker_thread+0x89f/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
hfs: new node 0 already hashed?
------------[ cut here ]------------
1
WARNING: fs/hfs/bnode.c:520 at hfs_bnode_create+0x461/0x4f0, CPU#1: kworker/u10:5/1092
Modules linked in:
CPU: 1 UID: 0 PID: 1092 Comm: kworker/u10:5 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: a7 8b 89 ee e8 d0 9a 82 fe e9 cf fc ff ff e8 86 8b 1d ff 4c 89 ef e8 0e 59 d6 08 48 c7 c7 e0 87 a7 8b 89 ee e8 b0 9a 82 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:ffffc9000812ec20 EFLAGS: 00010246

RAX: 000000000000001f RBX: ffff88801cd42000 RCX: 6d56555a8f2ae500
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1c3ce48 R12: 0000000000000000
R13: ffff88801cd420e0 R14: ffff8881013a2800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8882a9926000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffd9056fc4 CR3: 0000000110e8e000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 hfs_bmap_alloc+0x5c1/0x650
 hfs_btree_inc_height+0x100/0xad0
 hfs_brec_insert+0x7ef/0xc90
 __hfs_ext_write_extent+0x2a1/0x470
 hfs_ext_write_extent+0x17e/0x210
 hfs_write_inode+0x117/0x960
 __writeback_single_inode+0x7e1/0x1230
 writeback_sb_inodes+0x92c/0x1820
 wb_writeback+0x445/0xad0
 wb_workfn+0x3f8/0xef0
 process_scheduled_works+0xaec/0x17a0
 worker_thread+0x89f/0xd90
 kthread+0x726/0x8b0
 ret_from_fork+0x51b/0xa40
 ret_from_fork_asm+0x1a/0x30
 </TASK>
