loop0: detected capacity change from 0 to 64
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc6-syzkaller-00188-gfee3e843b309 #0 Not tainted
------------------------------------------------------
syz.0.4583/16916 is trying to acquire lock:
ffff88805b9ecef8 (&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:
ffff88805b5520b0 (&tree->tree_lock#2/1){+.+.}-{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#2/1){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       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_mkdir+0x6f/0xe0 fs/hfs/dir.c:232
       vfs_mkdir+0x593/0x8c0 fs/namei.c:4359
       do_mkdirat+0x304/0x3e0 fs/namei.c:4392
       __do_sys_mkdirat fs/namei.c:4409 [inline]
       __se_sys_mkdirat fs/namei.c:4407 [inline]
       __x64_sys_mkdirat+0x83/0xb0 fs/namei.c:4407
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x260 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 kernel/locking/lockdep.c:3909 [inline]
       __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
       lock_acquire kernel/locking/lockdep.c:5866 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
       __mutex_lock_common kernel/locking/mutex.c:601 [inline]
       __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
       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:2149
       block_write_begin+0x9a/0x1d0 fs/buffer.c:2260
       cont_write_begin+0x61b/0x950 fs/buffer.c:2599
       hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
       cont_expand_zero fs/buffer.c:2526 [inline]
       cont_write_begin+0x350/0x950 fs/buffer.c:2589
       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+0x15b/0x220 fs/open.c:65
       do_ftruncate+0x5a9/0x960 fs/open.c:192
       do_sys_ftruncate+0x61/0xa0 fs/open.c:207
       __do_sys_ftruncate fs/open.c:212 [inline]
       __se_sys_ftruncate fs/open.c:210 [inline]
       __x64_sys_ftruncate+0x58/0x80 fs/open.c:210
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x260 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.0.4583/16916:
 #0: ffff88803248e420 (sb_writers#25){.+.+}-{0:0}, at: do_sys_ftruncate+0x61/0xa0 fs/open.c:207
 #1: ffff88805b9ef120 (&sb->s_type->i_mutex_key#32){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff88805b9ef120 (&sb->s_type->i_mutex_key#32){+.+.}-{4:4}, at: do_truncate+0x14a/0x220 fs/open.c:63
 #2: ffff88805b9eef78 (&HFS_I(inode)->extents_lock#2){+.+.}-{4:4}, at: hfs_extend_file+0xa1/0xb10 fs/hfs/extent.c:397
 #3: ffff88805b5520b0 (&tree->tree_lock#2/1){+.+.}-{4:4}, at: hfs_find_init+0x183/0x220 fs/hfs/bfind.c:33

stack backtrace:
CPU: 1 UID: 0 PID: 16916 Comm: syz.0.4583 Not tainted 6.15.0-rc6-syzkaller-00188-gfee3e843b309 #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:2079
 check_noncircular+0x14c/0x170 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 kernel/locking/lockdep.c:3909 [inline]
 __lock_acquire+0x1173/0x1ba0 kernel/locking/lockdep.c:5235
 lock_acquire kernel/locking/lockdep.c:5866 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:746
 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:2149
 block_write_begin+0x9a/0x1d0 fs/buffer.c:2260
 cont_write_begin+0x61b/0x950 fs/buffer.c:2599
 hfs_write_begin+0x64/0x120 fs/hfs/inode.c:52
 cont_expand_zero fs/buffer.c:2526 [inline]
 cont_write_begin+0x350/0x950 fs/buffer.c:2589
 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+0x15b/0x220 fs/open.c:65
 do_ftruncate+0x5a9/0x960 fs/open.c:192
 do_sys_ftruncate+0x61/0xa0 fs/open.c:207
 __do_sys_ftruncate fs/open.c:212 [inline]
 __se_sys_ftruncate fs/open.c:210 [inline]
 __x64_sys_ftruncate+0x58/0x80 fs/open.c:210
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68d758e969
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:00007f68d845b038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f68d77b5fa0 RCX: 00007f68d758e969
RDX: 0000000000000000 RSI: 000000000000c17a RDI: 0000000000000004
RBP: 00007f68d7610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f68d77b5fa0 R15: 00007ffe9e5fc258
 </TASK>