============================================
WARNING: possible recursive locking detected
6.15.0-rc4-syzkaller-00208-g00b827f0cffa #0 Not tainted
--------------------------------------------
syz.0.0/5312 is trying to acquire lock:
ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_free_blocks fs/udf/balloc.c:375 [inline]
ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_free_blocks+0x9e2/0x17f0 fs/udf/balloc.c:677

but task is already holding lock:
ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_new_block+0xfab/0x1ba0 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.0.0/5312:
 #0: ffff88804301c420 (sb_writers#12){.+.+}-{0:0}, at: do_coredump+0x1e96/0x2a30 fs/coredump.c:758
 #1: ffff888051521c20 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #1: ffff888051521c20 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: udf_file_write_iter+0x6e/0x6c0 fs/udf/file.c:95
 #2: ffff888051521a50 (&ei->i_data_sem#2){++++}-{4:4}, at: udf_map_block+0x291/0x42a0 fs/udf/inode.c:439
 #3: ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_table_new_block fs/udf/balloc.c:581 [inline]
 #3: ffff88801fd70528 (&sbi->s_alloc_mutex){+.+.}-{4:4}, at: udf_new_block+0xfab/0x1ba0 fs/udf/balloc.c:725

stack backtrace:
CPU: 0 UID: 0 PID: 5312 Comm: syz.0.0 Not tainted 6.15.0-rc4-syzkaller-00208-g00b827f0cffa #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3042
 check_deadlock kernel/locking/lockdep.c:3094 [inline]
 validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3896
 __lock_acquire+0xaac/0xd20 kernel/locking/lockdep.c:5235
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5866
 __mutex_lock_common kernel/locking/mutex.c:601 [inline]
 __mutex_lock+0x182/0xe80 kernel/locking/mutex.c:746
 udf_table_free_blocks fs/udf/balloc.c:375 [inline]
 udf_free_blocks+0x9e2/0x17f0 fs/udf/balloc.c:677
 udf_delete_aext+0x4df/0xbc0 fs/udf/inode.c:2373
 udf_table_new_block fs/udf/balloc.c:645 [inline]
 udf_new_block+0x1404/0x1ba0 fs/udf/balloc.c:725
 inode_getblk fs/udf/inode.c:895 [inline]
 udf_map_block+0x12b1/0x42a0 fs/udf/inode.c:447
 __udf_get_block+0x52/0x250 fs/udf/inode.c:461
 __block_write_begin_int+0x6b2/0x1900 fs/buffer.c:2151
 block_write_begin+0x8a/0x120 fs/buffer.c:2262
 udf_write_begin+0x100/0x260 fs/udf/inode.c:256
 generic_perform_write+0x2c4/0x910 mm/filemap.c:4103
 udf_file_write_iter+0x2d5/0x6c0 fs/udf/file.c:111
 __kernel_write_iter+0x390/0x860 fs/read_write.c:617
 dump_emit_page fs/coredump.c:885 [inline]
 dump_user_range+0x830/0xc20 fs/coredump.c:959
 elf_core_dump+0x32ed/0x3900 fs/binfmt_elf.c:2128
 do_coredump+0x1ec8/0x2a30 fs/coredump.c:759
 get_signal+0x10d9/0x1310 kernel/signal.c:3019
 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 irqentry_exit_to_user_mode+0x81/0x120 kernel/entry/common.c:231
 exc_page_fault+0x91/0x110 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f756938e971
Code: 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 83 c8 ff c3 66 2e 0f 1f
RSP: 002b:fffffffffffffef0 EFLAGS: 00010217
RAX: 0000000000000000 RBX: 00007f75695b6080 RCX: 00007f756938e969
RDX: 0000000000000000 RSI: fffffffffffffef0 RDI: 0000000000a00200
RBP: 00007f7569410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f75695b6080 R15: 00007ffe7eff1758
 </TASK>