loop5: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking depend[  865.029869][T15431] WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.5.904/15431 is trying to acquire lock:
ffff888034002568 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0 fs/hfs/extent.c:397

but task is already holding lock:
ffff8880363140a0 (&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+0x35c/0x15e0 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
       hfs_cat_create+0x20f/0x800 fs/hfs/catalog.c:104
       hfs_create+0x66/0xe0 fs/hfs/dir.c:202
       lookup_open fs/namei.c:4449 [inline]
       open_last_lookups fs/namei.c:4549 [inline]
       path_openat+0x1902/0x3e70 fs/namei.c:4793
       do_filp_open+0x22d/0x490 fs/namei.c:4823
       do_sys_openat2+0x12f/0x220 fs/open.c:1430
       do_sys_open fs/open.c:1436 [inline]
       __do_sys_openat fs/open.c:1452 [inline]
       __se_sys_openat fs/open.c:1447 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1447
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xe2/0xf80 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x330 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+0xf2/0x15e0 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_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
       hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
       hfs_extend_file+0x39b/0x15e0 fs/hfs/extent.c:401
       hfs_get_block+0x412/0xc50 fs/hfs/extent.c:353
       __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2145
       block_write_begin fs/buffer.c:2256 [inline]
       cont_write_begin+0x737/0xae0 fs/buffer.c:2594
       hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
       cont_expand_zero fs/buffer.c:2522 [inline]
       cont_write_begin+0x2e7/0xae0 fs/buffer.c:2584
       hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
       generic_perform_write+0x2af/0x8b0 mm/filemap.c:4314
       generic_file_write_iter+0x14b/0x690 mm/filemap.c:4457
       new_sync_write fs/read_write.c:593 [inline]
       vfs_write+0x629/0xba0 fs/read_write.c:686
       ksys_pwrite64 fs/read_write.c:793 [inline]
       __do_sys_pwrite64 fs/read_write.c:801 [inline]
       __se_sys_pwrite64 fs/read_write.c:798 [inline]
       __x64_sys_pwrite64+0x19c/0x230 fs/read_write.c:798
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
       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.5.904/15431:
 #0: ffff888038196480 (sb_writers#30){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline]
 #0: ffff888038196480 (sb_writers#30){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682
 #1: ffff888034003d00 (&sb->s_type->i_mutex_key#35){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
 #1: ffff888034003d00 (&sb->s_type->i_mutex_key#35){+.+.}-{4:4}, at: generic_file_write_iter+0x11f/0x690 mm/filemap.c:4454
 #2: ffff888034003b28 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf2/0x15e0 fs/hfs/extent.c:397
 #3: ffff8880363140a0 (&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: 15431 Comm: syz.5.904 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 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+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x330 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+0xf2/0x15e0 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_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x39b/0x15e0 fs/hfs/extent.c:401
 hfs_get_block+0x412/0xc50 fs/hfs/extent.c:353
 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2145
 block_write_begin fs/buffer.c:2256 [inline]
 cont_write_begin+0x737/0xae0 fs/buffer.c:2594
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
 cont_expand_zero fs/buffer.c:2522 [inline]
 cont_write_begin+0x2e7/0xae0 fs/buffer.c:2584
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
 generic_perform_write+0x2af/0x8b0 mm/filemap.c:4314
 generic_file_write_iter+0x14b/0x690 mm/filemap.c:4457
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x629/0xba0 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x19c/0x230 fs/read_write.c:798
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5854cacb9
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:00007fd583726028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fd585745fa0 RCX: 00007fd5854cacb9
RDX: 000000000000ff10 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007fd585538bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c61 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd585746038 R14: 00007fd585745fa0 R15: 00007ffd10913ff8
 </TASK>
------------[ cut here ]------------
rtmutex deadlock detected
WARNING: kernel/locking/rtmutex.c:1674 at rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674, CPU#1: syz.5.904/15431
Modules linked in:
CPU: 1 UID: 0 PID: 15431 Comm: syz.5.904 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rt_mutex_handle_deadlock+0x21/0xb0 kernel/locking/rtmutex.c:1674
Code: 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 53 83 ff dd 0f 85 81 00 00 00 48 89 f7 e8 96 39 01 00 48 8d 3d 2f 5e 2f 04 <67> 48 0f b9 3a 4c 8d 3d 00 00 00 00 65 48 8b 1d c3 39 05 07 4c 8d
RSP: 0018:ffffc90005c2ebd0 EFLAGS: 00010286
RAX: 0000000080000000 RBX: ffffc90005c2ec60 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8b5f6240 RDI: ffffffff8f1e9460
RBP: ffffc90005c2ed68 R08: ffffffff8f1b7077 R09: 1ffffffff1e36e0e
R10: dffffc0000000000 R11: fffffbfff1e36e0f R12: 1ffff92000b85d88
R13: ffffffff8aef30ed R14: ffff888036314048 R15: dffffc0000000000
FS:  00007fd5837266c0(0000) GS:ffff8881269d9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd585518400 CR3: 0000000061c5a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1734 [inline]
 __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
 rt_mutex_slowlock+0x6c0/0x710 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline]
 mutex_lock_nested+0x168/0x1d0 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+0x35c/0x15e0 fs/hfs/extent.c:401
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:269
 __hfs_ext_write_extent+0x1fa/0x470 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6b/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x39b/0x15e0 fs/hfs/extent.c:401
 hfs_get_block+0x412/0xc50 fs/hfs/extent.c:353
 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2145
 block_write_begin fs/buffer.c:2256 [inline]
 cont_write_begin+0x737/0xae0 fs/buffer.c:2594
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
 cont_expand_zero fs/buffer.c:2522 [inline]
 cont_write_begin+0x2e7/0xae0 fs/buffer.c:2584
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:53
 generic_perform_write+0x2af/0x8b0 mm/filemap.c:4314
 generic_file_write_iter+0x14b/0x690 mm/filemap.c:4457
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x629/0xba0 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x19c/0x230 fs/read_write.c:798
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5854cacb9
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:00007fd583726028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007fd585745fa0 RCX: 00007fd5854cacb9
RDX: 000000000000ff10 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007fd585538bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000008000c61 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd585746038 R14: 00007fd585745fa0 R15: 00007ffd10913ff8
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	41 57                	push   %r15
   b:	41 56                	push   %r14
   d:	41 55                	push   %r13
   f:	41 54                	push   %r12
  11:	53                   	push   %rbx
  12:	83 ff dd             	cmp    $0xffffffdd,%edi
  15:	0f 85 81 00 00 00    	jne    0x9c
  1b:	48 89 f7             	mov    %rsi,%rdi
  1e:	e8 96 39 01 00       	call   0x139b9
  23:	48 8d 3d 2f 5e 2f 04 	lea    0x42f5e2f(%rip),%rdi        # 0x42f5e59
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	4c 8d 3d 00 00 00 00 	lea    0x0(%rip),%r15        # 0x36
  36:	65 48 8b 1d c3 39 05 	mov    %gs:0x70539c3(%rip),%rbx        # 0x7053a01
  3d:	07
  3e:	4c                   	rex.WR
  3f:	8d                   	.byte 0x8d