UDF-fs: error (device loop0): udf_verify_fi: directory (ino 1376) has entry at pos 0 with incorrect tag 0
==================================================================
BUG: KASAN: use-after-free in crc_itu_t+0x1b2/0x280 lib/crc-itu-t.c:60
Read of size 1 at addr ffff88807bba7000 by task syz-executor/4855

CPU: 1 PID: 4855 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 crc_itu_t+0x1b2/0x280 lib/crc-itu-t.c:60
 udf_finalize_lvid fs/udf/super.c:2057 [inline]
 udf_sync_fs+0x1ac/0x380 fs/udf/super.c:2413
 sync_filesystem+0xe6/0x220 fs/sync.c:56
 generic_shutdown_super+0x6b/0x300 fs/super.c:448
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x42d/0x4e0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x626/0x20c0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 __do_sys_exit_group kernel/exit.c:1008 [inline]
 __se_sys_exit_group kernel/exit.c:1006 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1006
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f06eee22379
Code: Unable to access opcode bytes at RIP 0x7f06eee2234f.
RSP: 002b:00007fffebbc3f38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007f06eeeb5235 RCX: 00007f06eee22379
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000010 R08: 0000000000000000 R09: 00007f06eeeb51c3
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffebbc51f0
R13: 00007f06eeeb51c3 R14: 000055559161b4e8 R15: 00007fffebbc62c0
 </TASK>

The buggy address belongs to the page:
page:ffffea0001eee9c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bba7
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00005ee1c8 ffffea00008e5b88 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x500dc0(GFP_USER|__GFP_ZERO|__GFP_ACCOUNT), pid 5104, ts 99881917066, free_ts 99884163958
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 pmd_alloc_one include/asm-generic/pgalloc.h:126 [inline]
 __pmd_alloc+0xa6/0x750 mm/memory.c:4958
 pmd_alloc include/linux/mm.h:2191 [inline]
 copy_pmd_range mm/memory.c:1147 [inline]
 copy_pud_range mm/memory.c:1204 [inline]
 copy_p4d_range mm/memory.c:1228 [inline]
 copy_page_range+0x2bf8/0x3230 mm/memory.c:1301
 dup_mmap kernel/fork.c:615 [inline]
 dup_mm kernel/fork.c:1466 [inline]
 copy_mm+0xc86/0x13f0 kernel/fork.c:1518
 copy_process+0x17eb/0x3e20 kernel/fork.c:2290
 kernel_clone+0x23f/0x990 kernel/fork.c:2679
 __do_sys_clone kernel/fork.c:2796 [inline]
 __se_sys_clone kernel/fork.c:2780 [inline]
 __x64_sys_clone+0x19a/0x210 kernel/fork.c:2780
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page_list+0x119/0x820 mm/page_alloc.c:3433
 release_pages+0x186c/0x1be0 mm/swap.c:963
 tlb_batch_pages_flush mm/mmu_gather.c:50 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:241 [inline]
 tlb_flush_mmu mm/mmu_gather.c:248 [inline]
 tlb_finish_mmu+0x1b4/0x370 mm/mmu_gather.c:371
 exit_mmap+0x3d0/0x640 mm/mmap.c:3218
 __mmput+0x115/0x3b0 kernel/fork.c:1127
 exit_mm+0x588/0x6e0 kernel/exit.c:550
 do_exit+0x5a9/0x20c0 kernel/exit.c:870
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 __do_sys_exit_group kernel/exit.c:1008 [inline]
 __se_sys_exit_group kernel/exit.c:1006 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1006
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
 ffff88807bba6f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807bba6f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807bba7000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807bba7080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807bba7100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================