======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.4.6572/21152 is trying to acquire lock:
ffff8880573868f0 (&sbi->alloc_mutex){+.+.}-{4:4}, at: hfsplus_block_allocate+0xa9/0xd30 fs/hfsplus/bitmap.c:35

but task is already holding lock:
ffff88805016c5c0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21c/0x1df0 fs/hfsplus/extents.c:457

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19c/0x15a0 kernel/locking/mutex.c:821
       hfsplus_get_block+0x391/0x1610 fs/hfsplus/extents.c:264
       block_read_full_folio+0x2db/0x8d0 fs/buffer.c:2312
       filemap_read_folio+0x12c/0x3a0 mm/filemap.c:2520
       do_read_cache_folio+0x354/0x590 mm/filemap.c:4156
       do_read_cache_page mm/filemap.c:4222 [inline]
       read_cache_page+0x5d/0x170 mm/filemap.c:4231
       read_mapping_page include/linux/pagemap.h:1009 [inline]
       hfsplus_block_allocate+0xf7/0xd30 fs/hfsplus/bitmap.c:37
       hfsplus_file_extend+0xb77/0x1df0 fs/hfsplus/extents.c:468
       hfsplus_get_block+0x41f/0x1610 fs/hfsplus/extents.c:249
       __block_write_begin_int+0x6c2/0x1900 fs/buffer.c:2034
       block_write_begin fs/buffer.c:2148 [inline]
       cont_write_begin+0x71b/0xac0 fs/buffer.c:2510
       hfsplus_write_begin+0x126/0x1e0 fs/hfsplus/inode.c:56
       page_symlink+0x27a/0x440 fs/namei.c:6651
       hfsplus_symlink+0xd3/0x390 fs/hfsplus/dir.c:478
       vfs_symlink+0x18b/0x330 fs/namei.c:5889
       filename_symlinkat+0x1cd/0x410 fs/namei.c:5914
       __do_sys_symlink fs/namei.c:5941 [inline]
       __se_sys_symlink+0x4d/0x2b0 fs/namei.c:5937
       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 (&sbi->alloc_mutex){+.+.}-{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+0x15ff/0x2e50 kernel/locking/lockdep.c:5254
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19c/0x15a0 kernel/locking/mutex.c:821
       hfsplus_block_allocate+0xa9/0xd30 fs/hfsplus/bitmap.c:35
       hfsplus_file_extend+0xb77/0x1df0 fs/hfsplus/extents.c:468
       hfsplus_bmap_reserve+0x170/0x590 fs/hfsplus/btree.c:512
       hfsplus_create_attr+0x1ce/0x3a0 fs/hfsplus/attributes.c:288
       __hfsplus_setxattr+0x706/0x2800 fs/hfsplus/xattr.c:453
       hfsplus_setxattr+0x124/0x340 fs/hfsplus/xattr.c:554
       hfsplus_trusted_setxattr+0x40/0x60 fs/hfsplus/xattr_trusted.c:30
       __vfs_setxattr+0x442/0x480 fs/xattr.c:223
       __vfs_setxattr_noperm+0x12a/0x660 fs/xattr.c:257
       vfs_setxattr+0x163/0x360 fs/xattr.c:344
       do_setxattr fs/xattr.c:662 [inline]
       filename_setxattr+0x296/0x630 fs/xattr.c:690
       path_setxattrat+0x408/0x450 fs/xattr.c:734
       __do_sys_setxattr fs/xattr.c:768 [inline]
       __se_sys_setxattr fs/xattr.c:764 [inline]
       __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:764
       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(&HFSPLUS_I(inode)->extents_lock);
                               lock(&sbi->alloc_mutex);
                               lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&sbi->alloc_mutex);

 *** DEADLOCK ***

locks held by syz.4.6572/21152: 5, last CPU#0:
 #0: ffff88807f554460 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
 #1: ffff88805016a818 (&sb->s_type->i_mutex_key#38){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #1: ffff88805016a818 (&sb->s_type->i_mutex_key#38){+.+.}-{4:4}, at: vfs_setxattr+0x13e/0x360 fs/xattr.c:343
 #2: ffff88807d0960a8 (&tree->tree_lock){+.+.}-{4:4}, at: hfsplus_find_init+0x179/0x2e0 fs/hfsplus/bfind.c:29
 #3: ffff8880507660a8 (&tree->tree_lock/2){+.+.}-{4:4}, at: hfsplus_find_init+0x179/0x2e0 fs/hfsplus/bfind.c:29
 #4: ffff88805016c5c0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21c/0x1df0 fs/hfsplus/extents.c:457

stack backtrace:
CPU: 0 UID: 0 PID: 21152 Comm: syz.4.6572 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2059
 check_noncircular+0x12f/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+0x15ff/0x2e50 kernel/locking/lockdep.c:5254
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5908
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x19c/0x15a0 kernel/locking/mutex.c:821
 hfsplus_block_allocate+0xa9/0xd30 fs/hfsplus/bitmap.c:35
 hfsplus_file_extend+0xb77/0x1df0 fs/hfsplus/extents.c:468
 hfsplus_bmap_reserve+0x170/0x590 fs/hfsplus/btree.c:512
 hfsplus_create_attr+0x1ce/0x3a0 fs/hfsplus/attributes.c:288
 __hfsplus_setxattr+0x706/0x2800 fs/hfsplus/xattr.c:453
 hfsplus_setxattr+0x124/0x340 fs/hfsplus/xattr.c:554
 hfsplus_trusted_setxattr+0x40/0x60 fs/hfsplus/xattr_trusted.c:30
 __vfs_setxattr+0x442/0x480 fs/xattr.c:223
 __vfs_setxattr_noperm+0x12a/0x660 fs/xattr.c:257
 vfs_setxattr+0x163/0x360 fs/xattr.c:344
 do_setxattr fs/xattr.c:662 [inline]
 filename_setxattr+0x296/0x630 fs/xattr.c:690
 path_setxattrat+0x408/0x450 fs/xattr.c:734
 __do_sys_setxattr fs/xattr.c:768 [inline]
 __se_sys_setxattr fs/xattr.c:764 [inline]
 __x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:764
 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: 0033:0x7f67a519e159
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:00007f67a5fb3028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f67a5425fa0 RCX: 00007f67a519e159
RDX: 0000000000000000 RSI: 00002000000003c0 RDI: 0000200000000380
RBP: 00007f67a5235024 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f67a5426038 R14: 00007f67a5425fa0 R15: 00007fff74f98fb8
 </TASK>