======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u8:6/1103 is trying to acquire lock:
ffff88805ffe0128 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397

but task is already holding lock:
ffff88805ff9a0a0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock#2/1){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
       hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_extend_file+0x2f6/0x1540 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
       hfs_cat_create+0x1c5/0x770 fs/hfs/catalog.c:104
       hfs_create+0x66/0xe0 fs/hfs/dir.c:202
       lookup_open fs/namei.c:4440 [inline]
       open_last_lookups fs/namei.c:4540 [inline]
       path_openat+0x18d1/0x3df0 fs/namei.c:4784
       do_filp_open+0x1fa/0x410 fs/namei.c:4814
       do_sys_openat2+0x121/0x200 fs/open.c:1430
       do_sys_open fs/open.c:1436 [inline]
       __do_sys_open fs/open.c:1444 [inline]
       __se_sys_open fs/open.c:1440 [inline]
       __x64_sys_open+0x11e/0x150 fs/open.c:1440
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
       __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
       mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
       hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
       __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
       hfs_ext_write_extent+0x161/0x1e0 fs/hfs/extent.c:144
       hfs_write_inode+0xc6/0x8a0 fs/hfs/inode.c:441
       write_inode fs/fs-writeback.c:1582 [inline]
       __writeback_single_inode+0x7e4/0x1240 fs/fs-writeback.c:1802
       writeback_sb_inodes+0x8c8/0x1840 fs/fs-writeback.c:2030
       wb_writeback+0x42b/0xaa0 fs/fs-writeback.c:2216
       wb_do_writeback fs/fs-writeback.c:2363 [inline]
       wb_workfn+0x3fe/0xee0 fs/fs-writeback.c:2403
       process_one_work kernel/workqueue.c:3257 [inline]
       process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
       worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
       kthread+0x711/0x8a0 kernel/kthread.c:463
       ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

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 ***

3 locks held by kworker/u8:6/1103:
 #0: ffff88814049a938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
 #0: ffff88814049a938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
 #1: ffffc90004d1fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
 #1: ffffc90004d1fbc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
 #2: ffff88805ff9a0a0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18e/0x300 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 0 UID: 0 PID: 1103 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
 __mutex_lock_common kernel/locking/rtmutex_api.c:533 [inline]
 mutex_lock_nested+0x5a/0x1d0 kernel/locking/rtmutex_api.c:552
 hfs_extend_file+0xda/0x1540 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
 hfs_ext_write_extent+0x161/0x1e0 fs/hfs/extent.c:144
 hfs_write_inode+0xc6/0x8a0 fs/hfs/inode.c:441
 write_inode fs/fs-writeback.c:1582 [inline]
 __writeback_single_inode+0x7e4/0x1240 fs/fs-writeback.c:1802
 writeback_sb_inodes+0x8c8/0x1840 fs/fs-writeback.c:2030
 wb_writeback+0x42b/0xaa0 fs/fs-writeback.c:2216
 wb_do_writeback fs/fs-writeback.c:2363 [inline]
 wb_workfn+0x3fe/0xee0 fs/fs-writeback.c:2403
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
hfs: new node 0 already hashed?
------------[ cut here ]------------
WARNING: fs/hfs/bnode.c:520 at hfs_bnode_create+0x461/0x4f0 fs/hfs/bnode.c:520, CPU#0: kworker/u8:6/1103
Modules linked in:
CPU: 0 UID: 0 PID: 1103 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:hfs_bnode_create+0x461/0x4f0 fs/hfs/bnode.c:520
Code: 02 8b 89 ee e8 00 a1 90 fe e9 cf fc ff ff e8 c6 f9 28 ff 4c 89 ef e8 de 39 3d 08 48 c7 c7 80 41 02 8b 89 ee e8 e0 a0 90 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:ffffc90004d1ec20 EFLAGS: 00010246
RAX: 000000000000001f RBX: ffff88805ff9a000 RCX: 373c03b92892dc00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1017104923 R12: 0000000000000000
R13: ffff88805ff9a0d0 R14: ffff88802f493800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc6fd61d000 CR3: 00000000206b4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 hfs_bmap_alloc+0x5bb/0x640 fs/hfs/btree.c:326
 hfs_btree_inc_height+0xf6/0xac0 fs/hfs/brec.c:490
 hfs_brec_insert+0x7ee/0xc80 fs/hfs/brec.c:148
 __hfs_ext_write_extent+0x2a1/0x470 fs/hfs/extent.c:124
 hfs_ext_write_extent+0x161/0x1e0 fs/hfs/extent.c:144
 hfs_write_inode+0xc6/0x8a0 fs/hfs/inode.c:441
 write_inode fs/fs-writeback.c:1582 [inline]
 __writeback_single_inode+0x7e4/0x1240 fs/fs-writeback.c:1802
 writeback_sb_inodes+0x8c8/0x1840 fs/fs-writeback.c:2030
 wb_writeback+0x42b/0xaa0 fs/fs-writeback.c:2216
 wb_do_writeback fs/fs-writeback.c:2363 [inline]
 wb_workfn+0x3fe/0xee0 fs/fs-writeback.c:2403
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>