============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.5.6/5862 is trying to acquire lock:
ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_free_blocks fs/udf/balloc.c:375 [inline]
ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_free_blocks+0x8de/0x1210 fs/udf/balloc.c:677

but task is already holding lock:
ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_new_block+0x39f/0x17a0 fs/udf/balloc.c:725

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

       CPU0
       ----
  lock(&sbi->s_alloc_mutex);
  lock(&sbi->s_alloc_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

4 locks held by syz.5.6/5862:
 #0: ffff8880530d6410 (sb_writers#12){.+.+}-{0:0}, at: splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103
 #1: ffff888055301ca8 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1029 [inline]
 #1: ffff888055301ca8 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: udf_file_write_iter+0x7b/0x780 fs/udf/file.c:96
 #2: ffff888055301a88 (&ei->i_data_sem#2){++++}-{4:4}, at: udf_map_block+0x159/0x5c0 fs/udf/inode.c:445
 #3: ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
 #3: ffff88802d0e1d20 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_new_block+0x39f/0x17a0 fs/udf/balloc.c:725

stack backtrace:
CPU: 1 UID: 0 PID: 5862 Comm: syz.5.6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041
 check_deadlock kernel/locking/lockdep.c:3093 [inline]
 validate_chain kernel/locking/lockdep.c:3895 [inline]
 __lock_acquire+0x12bb/0x2630 kernel/locking/lockdep.c:5237
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:820
 udf_table_free_blocks fs/udf/balloc.c:375 [inline]
 udf_free_blocks+0x8de/0x1210 fs/udf/balloc.c:677
 udf_delete_aext+0x4d8/0xdd0 fs/udf/inode.c:2381
 udf_table_new_block fs/udf/balloc.c:645 [inline]
 udf_new_block+0x13ed/0x17a0 fs/udf/balloc.c:725
 inode_getblk+0xc56/0x41b0 fs/udf/inode.c:900
 udf_map_block+0x2dd/0x5c0 fs/udf/inode.c:453
 __udf_get_block+0x98/0x330 fs/udf/inode.c:467
 __block_write_begin_int+0x57a/0x19c0 fs/buffer.c:2042
 block_write_begin+0x9d/0x1d0 fs/buffer.c:2153
 udf_write_begin+0x217/0x300 fs/udf/inode.c:261
 generic_perform_write+0x292/0xa40 mm/filemap.c:4325
 __generic_file_write_iter+0x1f7/0x240 mm/filemap.c:4442
 udf_file_write_iter+0x231/0x780 fs/udf/file.c:112
 iter_file_splice_write+0x830/0x10a0 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x192/0x6c0 fs/splice.c:1159
 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x174/0x240 fs/splice.c:1228
 do_sendfile+0xadc/0xe20 fs/read_write.c:1372
 __do_sys_sendfile64 fs/read_write.c:1433 [inline]
 __se_sys_sendfile64 fs/read_write.c:1419 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1419
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x10b/0x860 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faee079ce59
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:00007faee16b7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007faee0a16090 RCX: 00007faee079ce59
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007faee0832d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0001000000201005 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faee0a16128 R14: 00007faee0a16090 R15: 00007ffd3b8a5b48
 </TASK>