loop4: detected capacity change from 0 to 1024
============================================
WARNING: possible recursive locking detected
6.14.0-syzkaller-11144-g1e7857b28020 #0 Not tainted
--------------------------------------------
syz.4.39/6166 is trying to acquire lock:
ffff888034f40108 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21d/0x1b70 fs/hfsplus/extents.c:458

but task is already holding lock:
ffff888034f44b48 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21d/0x1b70 fs/hfsplus/extents.c:458

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&HFSPLUS_I(inode)->extents_lock);
  lock(&HFSPLUS_I(inode)->extents_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by syz.4.39/6166:
 #0: ffff88805e186420 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3041 [inline]
 #0: ffff88805e186420 (sb_writers#12){.+.+}-{0:0}, at: vfs_writev+0x2d8/0xbc0 fs/read_write.c:1053
 #1: ffff888034f44d38 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888034f44d38 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: generic_file_write_iter+0xe2/0x5e0 mm/filemap.c:4254
 #2: ffff888034f44b48 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{4:4}, at: hfsplus_file_extend+0x21d/0x1b70 fs/hfsplus/extents.c:458
 #3: ffff88805e19c0b0 (&tree->tree_lock/1){+.+.}-{4:4}, at: hfsplus_find_init+0x14f/0x1d0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 0 UID: 0 PID: 6166 Comm: syz.4.39 Not tainted 6.14.0-syzkaller-11144-g1e7857b28020 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042
 check_deadlock kernel/locking/lockdep.c:3094 [inline]
 validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896
 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235
 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:587 [inline]
 __mutex_lock+0x1a5/0x10c0 kernel/locking/mutex.c:732
 hfsplus_file_extend+0x21d/0x1b70 fs/hfsplus/extents.c:458
 hfsplus_bmap_reserve+0x105/0x4e0 fs/hfsplus/btree.c:358
 __hfsplus_ext_write_extent+0x2a4/0x5c0 fs/hfsplus/extents.c:104
 __hfsplus_ext_cache_extent+0x84/0xe10 fs/hfsplus/extents.c:186
 hfsplus_ext_read_extent fs/hfsplus/extents.c:218 [inline]
 hfsplus_file_extend+0x48e/0x1b70 fs/hfsplus/extents.c:462
 hfsplus_get_block+0x408/0x14f0 fs/hfsplus/extents.c:245
 __block_write_begin_int+0x691/0x1930 fs/buffer.c:2116
 block_write_begin fs/buffer.c:2226 [inline]
 cont_write_begin+0x781/0xb40 fs/buffer.c:2565
 hfsplus_write_begin+0x68/0xb0 fs/hfsplus/inode.c:46
 generic_perform_write+0x329/0xa10 mm/filemap.c:4114
 generic_file_write_iter+0x10e/0x5e0 mm/filemap.c:4257
 do_iter_readv_writev+0x71f/0x9d0 fs/read_write.c:-1
 vfs_writev+0x38d/0xbc0 fs/read_write.c:1055
 do_pwritev fs/read_write.c:1151 [inline]
 __do_sys_pwritev2 fs/read_write.c:1209 [inline]
 __se_sys_pwritev2+0x1b8/0x2d0 fs/read_write.c:1200
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fb8d8d169
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:00007f7fb9c3b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007f7fb8fa5fa0 RCX: 00007f7fb8d8d169
RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000004
RBP: 00007f7fb8e0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7b R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7fb8fa5fa0 R15: 00007ffc84209a98
 </TASK>