syzbot

hfs: unable to locate alternate MDB
hfs: continuing without an alternate MDB
============================================
WARNING: possible recursive locking detected
6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted
--------------------------------------------
syz-executor147/5062 is trying to acquire lock:
ffff888023e740b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x16e/0x1f0

but task is already holding lock:
ffff888023e740b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x16e/0x1f0

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

       CPU0
       ----
  lock(&tree->tree_lock/1);
  lock(&tree->tree_lock/1);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

5 locks held by syz-executor147/5062:
 #0: ffff888023606420 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2853 [inline]
 #0: ffff888023606420 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x233/0xcb0 fs/read_write.c:586
 #1: ffff888022280fa8 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:793 [inline]
 #1: ffff888022280fa8 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: generic_file_write_iter+0x83/0x310 mm/filemap.c:4048
 #2: ffff888022280df8 (&HFS_I(inode)->extents_lock#2){+.+.}-{3:3}, at: hfs_extend_file+0xff/0x1450 fs/hfs/extent.c:397
 #3: ffff888023e740b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfs_find_init+0x16e/0x1f0
 #4: ffff8880222800f8 (&HFS_I(tree->inode)->extents_lock){+.+.}-{3:3}, at: hfs_extend_file+0xff/0x1450 fs/hfs/extent.c:397

stack backtrace:
CPU: 1 PID: 5062 Comm: syz-executor147 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_deadlock kernel/locking/lockdep.c:3062 [inline]
 validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
 __mutex_lock_common kernel/locking/mutex.c:608 [inline]
 __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752
 hfs_find_init+0x16e/0x1f0
 hfs_ext_read_extent fs/hfs/extent.c:200 [inline]
 hfs_extend_file+0x31b/0x1450 fs/hfs/extent.c:401
 hfs_bmap_reserve+0xd9/0x400 fs/hfs/btree.c:234
 __hfs_ext_write_extent+0x22e/0x4f0 fs/hfs/extent.c:121
 __hfs_ext_cache_extent+0x6a/0x990 fs/hfs/extent.c:174
 hfs_ext_read_extent fs/hfs/extent.c:202 [inline]
 hfs_extend_file+0x344/0x1450 fs/hfs/extent.c:401
 hfs_get_block+0x3e4/0xb60 fs/hfs/extent.c:353
 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2105
 __block_write_begin fs/buffer.c:2154 [inline]
 block_write_begin+0x9b/0x1e0 fs/buffer.c:2213
 cont_write_begin+0x645/0x890 fs/buffer.c:2567
 hfs_write_begin+0x8a/0xd0 fs/hfs/inode.c:53
 generic_perform_write+0x322/0x640 mm/filemap.c:3930
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4051
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa84/0xcb0 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_64+0xfb/0x240
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f0b1c5af679
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc1df27de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffc1df27fb8 RCX: 00007f0b1c5af679
RDX: 000000000208e24b RSI: 00000000200004c0 RDI: 0000000000000005
RBP: 00007f0b1c622610 R08: 0000000000000000 R09: 00007ffc1df27fb8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc1df27fa8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>