UDF-fs: error (device loop2): udf_verify_fi: directory (ino 1376) has entry at pos 0 with incorrect tag 0
UDF-fs: error (device loop2): udf_verify_fi: directory (ino 1376) has entry at pos 0 with incorrect tag 0
==================================================================
BUG: KASAN: use-after-free in crc_itu_t+0x1f5/0x280 lib/crc-itu-t.c:60
Read of size 1 at addr ffff888061da8000 by task syz-executor/4275

CPU: 1 PID: 4275 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 crc_itu_t+0x1f5/0x280 lib/crc-itu-t.c:60
 udf_finalize_lvid fs/udf/super.c:2054 [inline]
 udf_sync_fs+0x194/0x350 fs/udf/super.c:2410
 sync_filesystem+0xe6/0x220 fs/sync.c:56
 generic_shutdown_super+0x6b/0x340 fs/super.c:474
 kill_block_super+0x7c/0xe0 fs/super.c:1470
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x463/0x4f0 fs/namespace.c:1191
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb5cb98f749
Code: Unable to access opcode bytes at 0x7fb5cb98f71f.
RSP: 002b:00007fffdbcf13b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fb5cba13def RCX: 00007fb5cb98f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000010 R08: 00007fffdbcef156 R09: 00007fffdbcf2670
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffdbcf2670
R13: 00007fb5cba13d7d R14: 000055558f2d44a8 R15: 00007fffdbcf3740
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001876a00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x61da8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001878a88 ffffea0001878b08 0000000000000000
raw: 0000000000000000 0000000000000001 00000000ffffff7f 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 0x102cc2(GFP_HIGHUSER|__GFP_NOWARN), pid 5104, tgid 5094 (syz.4.121), ts 123741739282, free_ts 123823124792
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 vm_area_alloc_pages mm/vmalloc.c:3002 [inline]
 __vmalloc_area_node mm/vmalloc.c:3071 [inline]
 __vmalloc_node_range+0x959/0x1390 mm/vmalloc.c:3243
 __vmalloc_node mm/vmalloc.c:3308 [inline]
 vmalloc+0x75/0x80 mm/vmalloc.c:3341
 __snd_dma_alloc_pages sound/core/memalloc.c:40 [inline]
 snd_dma_alloc_dir_pages+0x158/0x230 sound/core/memalloc.c:74
 do_alloc_pages+0x11a/0x260 sound/core/pcm_memory.c:74
 snd_pcm_lib_malloc_pages+0x2fd/0x680 sound/core/pcm_memory.c:459
 snd_pcm_hw_params+0x77c/0x1c50 sound/core/pcm_native.c:771
 snd_pcm_oss_change_params_locked+0x222c/0x3ee0 sound/core/oss/pcm_oss.c:976
 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1115 [inline]
 snd_pcm_oss_make_ready+0x11b/0x330 sound/core/oss/pcm_oss.c:1174
 snd_pcm_oss_sync+0x198/0xc00 sound/core/oss/pcm_oss.c:1741
 snd_pcm_oss_release+0xfe/0x240 sound/core/oss/pcm_oss.c:2589
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479
 __vunmap+0x856/0xa00 mm/vmalloc.c:2726
 do_free_pages sound/core/pcm_memory.c:93 [inline]
 snd_pcm_lib_free_pages+0x1e4/0x2a0 sound/core/pcm_memory.c:499
 do_hw_free sound/core/pcm_native.c:888 [inline]
 snd_pcm_release_substream+0x29e/0x460 sound/core/pcm_native.c:2721
 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2412 [inline]
 snd_pcm_oss_release+0x180/0x240 sound/core/oss/pcm_oss.c:2591
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff888061da7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888061da7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888061da8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888061da8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888061da8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================