loop4: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 Not tainted
------------------------------------------------------
syz.4.1381/12572 is trying to acquire lock:
ffff888062f00778 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1230 fs/hfs/extent.c:397

but task is already holding lock:
ffff888064cc20b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x165/0x1e0 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}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
       hfs_find_init+0x165/0x1e0 fs/hfs/bfind.c:-1
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_extend_file+0x2ee/0x1230 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:234
       hfs_cat_create+0x1b3/0x640 fs/hfs/catalog.c:104
       hfs_create+0x66/0xe0 fs/hfs/dir.c:202
       lookup_open fs/namei.c:3701 [inline]
       open_last_lookups fs/namei.c:3800 [inline]
       path_openat+0x14f4/0x3830 fs/namei.c:4036
       do_filp_open+0x1fa/0x410 fs/namei.c:4066
       do_sys_openat2+0x121/0x1c0 fs/open.c:1429
       do_sys_open fs/open.c:1444 [inline]
       __do_sys_openat fs/open.c:1460 [inline]
       __se_sys_openat fs/open.c:1455 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1455
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 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:3166 [inline]
       check_prevs_add kernel/locking/lockdep.c:3285 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3909
       __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
       hfs_extend_file+0xda/0x1230 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:234
       __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+0x316/0x1230 fs/hfs/extent.c:401
       hfs_get_block+0x3d7/0xbd0 fs/hfs/extent.c:353
       __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2151
       block_write_begin fs/buffer.c:2262 [inline]
       cont_write_begin+0x789/0xb50 fs/buffer.c:2601
       hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52
       cont_expand_zero fs/buffer.c:2528 [inline]
       cont_write_begin+0x2fd/0xb50 fs/buffer.c:2591
       hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52
       hfs_file_truncate+0x190/0x9c0 fs/hfs/extent.c:494
       hfs_inode_setattr+0x4a9/0x670 fs/hfs/inode.c:654
       notify_change+0xb36/0xe40 fs/attr.c:552
       do_truncate+0x19a/0x220 fs/open.c:65
       do_ftruncate+0x489/0x540 fs/open.c:192
       do_sys_ftruncate fs/open.c:207 [inline]
       __do_sys_ftruncate fs/open.c:212 [inline]
       __se_sys_ftruncate fs/open.c:210 [inline]
       __x64_sys_ftruncate+0x92/0xf0 fs/open.c:210
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xf6/0x210 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.4.1381/12572:
 #0: ffff888058f62420 (sb_writers#31){.+.+}-{0:0}, at: do_ftruncate+0x42a/0x540 fs/open.c:191
 #1: ffff888062f06aa0 (&sb->s_type->i_mutex_key#37){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888062f06aa0 (&sb->s_type->i_mutex_key#37){+.+.}-{4:4}, at: do_truncate+0x186/0x220 fs/open.c:63
 #2: ffff888062f068f8 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xda/0x1230 fs/hfs/extent.c:397
 #3: ffff888064cc20b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x165/0x1e0 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 1 UID: 0 PID: 12572 Comm: syz.4.1381 Not tainted 6.15.0-rc5-syzkaller-00300-g3ce9925823c7 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2079
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2211
 check_prev_add kernel/locking/lockdep.c:3166 [inline]
 check_prevs_add kernel/locking/lockdep.c:3285 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3909
 __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
 hfs_extend_file+0xda/0x1230 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x107/0x430 fs/hfs/btree.c:234
 __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+0x316/0x1230 fs/hfs/extent.c:401
 hfs_get_block+0x3d7/0xbd0 fs/hfs/extent.c:353
 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2151
 block_write_begin fs/buffer.c:2262 [inline]
 cont_write_begin+0x789/0xb50 fs/buffer.c:2601
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2528 [inline]
 cont_write_begin+0x2fd/0xb50 fs/buffer.c:2591
 hfs_write_begin+0x66/0xb0 fs/hfs/inode.c:52
 hfs_file_truncate+0x190/0x9c0 fs/hfs/extent.c:494
 hfs_inode_setattr+0x4a9/0x670 fs/hfs/inode.c:654
 notify_change+0xb36/0xe40 fs/attr.c:552
 do_truncate+0x19a/0x220 fs/open.c:65
 do_ftruncate+0x489/0x540 fs/open.c:192
 do_sys_ftruncate fs/open.c:207 [inline]
 __do_sys_ftruncate fs/open.c:212 [inline]
 __se_sys_ftruncate fs/open.c:210 [inline]
 __x64_sys_ftruncate+0x92/0xf0 fs/open.c:210
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c4d78e969
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1c4e56c038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f1c4d9b5fa0 RCX: 00007f1c4d78e969
RDX: 0000000000000000 RSI: 000000000000c17a RDI: 0000000000000004
RBP: 00007f1c4d810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1c4d9b5fa0 R15: 00007ffcb2bc3388
 </TASK>