x_tables: duplicate underflow at hook 1
======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-syzkaller-00037-ge2291551827f #0 Not tainted
------------------------------------------------------
syz.2.3191/18088 is trying to acquire lock:
ffff888035821478 (&HFS_I(tree->inode)->extents_lock){+.+.}-{4:4}, at: hfs_extend_file+0xa1/0xb10 fs/hfs/extent.c:397

but task is already holding lock:
ffff8880348920b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x183/0x220 fs/hfs/bfind.c:33

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_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       hfs_find_init+0x183/0x220 fs/hfs/bfind.c:33
       hfs_ext_read_extent+0x19b/0x9e0 fs/hfs/extent.c:200
       hfs_extend_file+0x4e2/0xb10 fs/hfs/extent.c:401
       hfs_bmap_reserve+0x2a2/0x390 fs/hfs/btree.c:234
       hfs_cat_create+0x229/0x820 fs/hfs/catalog.c:104
       hfs_create+0x6b/0xf0 fs/hfs/dir.c:202
       lookup_open.isra.0+0x11d3/0x1580 fs/namei.c:3717
       open_last_lookups fs/namei.c:3816 [inline]
       path_openat+0x893/0x2cb0 fs/namei.c:4052
       do_filp_open+0x20b/0x470 fs/namei.c:4082
       do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
       do_sys_open fs/open.c:1452 [inline]
       __do_sys_openat fs/open.c:1468 [inline]
       __se_sys_openat fs/open.c:1463 [inline]
       __x64_sys_openat+0x174/0x210 fs/open.c:1463
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain kernel/locking/lockdep.c:3911 [inline]
       __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
       lock_acquire kernel/locking/lockdep.c:5871 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
       __mutex_lock_common kernel/locking/mutex.c:602 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
       hfs_extend_file+0xa1/0xb10 fs/hfs/extent.c:397
       hfs_bmap_reserve+0x2a2/0x390 fs/hfs/btree.c:234
       __hfs_ext_write_extent+0x3cf/0x520 fs/hfs/extent.c:121
       __hfs_ext_cache_extent fs/hfs/extent.c:174 [inline]
       hfs_ext_read_extent+0x807/0x9e0 fs/hfs/extent.c:202
       hfs_extend_file+0x4e2/0xb10 fs/hfs/extent.c:401
       hfs_get_block+0x17f/0x830 fs/hfs/extent.c:353
       __block_write_begin_int+0x4f4/0x16d0 fs/buffer.c:2151
       block_write_begin+0x9a/0x1d0 fs/buffer.c:2262
       cont_write_begin+0x61b/0x950 fs/buffer.c:2601
       hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
       cont_expand_zero fs/buffer.c:2528 [inline]
       cont_write_begin+0x350/0x950 fs/buffer.c:2591
       hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
       hfs_file_truncate+0xc0f/0xfc0 fs/hfs/extent.c:494
       hfs_inode_setattr+0x48e/0x5e0 fs/hfs/inode.c:654
       notify_change+0x6a9/0x1230 fs/attr.c:552
       do_truncate+0x1d7/0x230 fs/open.c:68
       do_ftruncate+0x5a9/0x970 fs/open.c:195
       do_sys_ftruncate+0x61/0xb0 fs/open.c:210
       __do_sys_ftruncate fs/open.c:215 [inline]
       __se_sys_ftruncate fs/open.c:213 [inline]
       __x64_sys_ftruncate+0x58/0x80 fs/open.c:213
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 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/1);
                               lock(&HFS_I(tree->inode)->extents_lock);
                               lock(&tree->tree_lock/1);
  lock(&HFS_I(tree->inode)->extents_lock);

 *** DEADLOCK ***

4 locks held by syz.2.3191/18088:
 #0: ffff888052b12428 (sb_writers#24){.+.+}-{0:0}, at: do_sys_ftruncate+0x61/0xb0 fs/open.c:210
 #1: ffff88804facbd20 (&sb->s_type->i_mutex_key#34){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:874 [inline]
 #1: ffff88804facbd20 (&sb->s_type->i_mutex_key#34){+.+.}-{4:4}, at: do_truncate+0x146/0x230 fs/open.c:63
 #2: ffff88804facbb78 (&HFS_I(inode)->extents_lock#2){+.+.}-{4:4}, at: hfs_extend_file+0xa1/0xb10 fs/hfs/extent.c:397
 #3: ffff8880348920b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfs_find_init+0x183/0x220 fs/hfs/bfind.c:33

stack backtrace:
CPU: 0 UID: 0 PID: 18088 Comm: syz.2.3191 Not tainted 6.16.0-rc6-syzkaller-00037-ge2291551827f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 __mutex_lock_common kernel/locking/mutex.c:602 [inline]
 __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747
 hfs_extend_file+0xa1/0xb10 fs/hfs/extent.c:397
 hfs_bmap_reserve+0x2a2/0x390 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x3cf/0x520 fs/hfs/extent.c:121
 __hfs_ext_cache_extent fs/hfs/extent.c:174 [inline]
 hfs_ext_read_extent+0x807/0x9e0 fs/hfs/extent.c:202
 hfs_extend_file+0x4e2/0xb10 fs/hfs/extent.c:401
 hfs_get_block+0x17f/0x830 fs/hfs/extent.c:353
 __block_write_begin_int+0x4f4/0x16d0 fs/buffer.c:2151
 block_write_begin+0x9a/0x1d0 fs/buffer.c:2262
 cont_write_begin+0x61b/0x950 fs/buffer.c:2601
 hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2528 [inline]
 cont_write_begin+0x350/0x950 fs/buffer.c:2591
 hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
 hfs_file_truncate+0xc0f/0xfc0 fs/hfs/extent.c:494
 hfs_inode_setattr+0x48e/0x5e0 fs/hfs/inode.c:654
 notify_change+0x6a9/0x1230 fs/attr.c:552
 do_truncate+0x1d7/0x230 fs/open.c:68
 do_ftruncate+0x5a9/0x970 fs/open.c:195
 do_sys_ftruncate+0x61/0xb0 fs/open.c:210
 __do_sys_ftruncate fs/open.c:215 [inline]
 __se_sys_ftruncate fs/open.c:213 [inline]
 __x64_sys_ftruncate+0x58/0x80 fs/open.c:213
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f32ad58e929
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:00007f32ae357038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f32ad7b6080 RCX: 00007f32ad58e929
RDX: 0000000000000000 RSI: 0000000002007ffb RDI: 000000000000000a
RBP: 00007f32ad610ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f32ad7b6080 R15: 00007fff0c2356e8
 </TASK>