======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.5.9058/26971 is trying to acquire lock:
ffff888066b9a320 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf9/0x1680 fs/hfs/extent.c:397

but task is already holding lock:
ffff88807bc280a8 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18d/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/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       hfs_find_init+0x18d/0x300 fs/hfs/bfind.c:-1
       hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
       hfs_extend_file+0x367/0x1680 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x108/0x430 fs/hfs/btree.c:399
       hfs_cat_create+0x23d/0x870 fs/hfs/catalog.c:104
       hfs_create+0x78/0xe0 fs/hfs/dir.c:196
       lookup_open+0xc0d/0x1a40 fs/namei.c:4567
       open_last_lookups fs/namei.c:4767 [inline]
       path_openat+0x677/0x1d60 fs/namei.c:4997
       do_file_open+0x23e/0x4a0 fs/namei.c:5029
       do_sys_openat2+0x115/0x200 fs/open.c:1417
       do_sys_open fs/open.c:1423 [inline]
       __do_sys_openat fs/open.c:1439 [inline]
       __se_sys_openat fs/open.c:1434 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1434
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3181 [inline]
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5253
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       hfs_extend_file+0xf9/0x1680 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x108/0x430 fs/hfs/btree.c:399
       __hfs_ext_write_extent+0x1fc/0x470 fs/hfs/extent.c:121
       __hfs_ext_cache_extent+0x6e/0x9b0 fs/hfs/extent.c:174
       hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
       hfs_extend_file+0x3ad/0x1680 fs/hfs/extent.c:401
       hfs_get_block+0x401/0xbf0 fs/hfs/extent.c:353
       __block_write_begin_int+0x6c2/0x1900 fs/buffer.c:2030
       block_write_begin fs/buffer.c:2144 [inline]
       cont_write_begin+0x71b/0xac0 fs/buffer.c:2506
       hfs_write_begin+0x123/0x1c0 fs/hfs/inode.c:62
       cont_expand_zero fs/buffer.c:2434 [inline]
       cont_write_begin+0x2d6/0xac0 fs/buffer.c:2496
       hfs_write_begin+0x123/0x1c0 fs/hfs/inode.c:62
       hfs_file_truncate+0x1d2/0xb70 fs/hfs/extent.c:495
       hfs_inode_setattr+0x4a3/0x6d0 fs/hfs/inode.c:688
       notify_change+0xbba/0xea0 fs/attr.c:556
       do_truncate+0x1c2/0x250 fs/open.c:68
       vfs_truncate+0x4b4/0x540 fs/open.c:118
       ksys_truncate+0xf3/0x1c0 fs/open.c:142
       __do_sys_truncate fs/open.c:154 [inline]
       __se_sys_truncate fs/open.c:152 [inline]
       __x64_sys_truncate+0x5b/0x70 fs/open.c:152
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       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 ***

locks held by syz.5.9058/26971: 4, last CPU#0:
 #0: ffff888022b30460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
 #1: ffff888066b9b600 (&sb->s_type->i_mutex_key#40){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:1030 [inline]
 #1: ffff888066b9b600 (&sb->s_type->i_mutex_key#40){+.+.}-{4:4}, at: do_truncate+0x18f/0x250 fs/open.c:63
 #2: ffff888066b9b460 (&HFS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xf9/0x1680 fs/hfs/extent.c:397
 #3: ffff88807bc280a8 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x18d/0x300 fs/hfs/bfind.c:-1

stack backtrace:
CPU: 0 UID: 0 PID: 26971 Comm: syz.5.9058 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2059
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2191
 check_prev_add kernel/locking/lockdep.c:3181 [inline]
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5253
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5886
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
 hfs_extend_file+0xf9/0x1680 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x108/0x430 fs/hfs/btree.c:399
 __hfs_ext_write_extent+0x1fc/0x470 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6e/0x9b0 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x3ad/0x1680 fs/hfs/extent.c:401
 hfs_get_block+0x401/0xbf0 fs/hfs/extent.c:353
 __block_write_begin_int+0x6c2/0x1900 fs/buffer.c:2030
 block_write_begin fs/buffer.c:2144 [inline]
 cont_write_begin+0x71b/0xac0 fs/buffer.c:2506
 hfs_write_begin+0x123/0x1c0 fs/hfs/inode.c:62
 cont_expand_zero fs/buffer.c:2434 [inline]
 cont_write_begin+0x2d6/0xac0 fs/buffer.c:2496
 hfs_write_begin+0x123/0x1c0 fs/hfs/inode.c:62
 hfs_file_truncate+0x1d2/0xb70 fs/hfs/extent.c:495
 hfs_inode_setattr+0x4a3/0x6d0 fs/hfs/inode.c:688
 notify_change+0xbba/0xea0 fs/attr.c:556
 do_truncate+0x1c2/0x250 fs/open.c:68
 vfs_truncate+0x4b4/0x540 fs/open.c:118
 ksys_truncate+0xf3/0x1c0 fs/open.c:142
 __do_sys_truncate fs/open.c:154 [inline]
 __se_sys_truncate fs/open.c:152 [inline]
 __x64_sys_truncate+0x5b/0x70 fs/open.c:152
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd63539e159
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:00007fd6361f2028 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fd635625fa0 RCX: 00007fd63539e159
RDX: 0000000000000000 RSI: 0000000001000707 RDI: 0000200000000340
RBP: 00007fd635435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd635626038 R14: 00007fd635625fa0 R15: 00007ffe58ffeca8
 </TASK>