================================================================== BUG: KASAN: use-after-free in crc_itu_t+0x1b2/0x280 lib/crc-itu-t.c:60 Read of size 1 at addr ffff8880717c0000 by task syz.1.1126/10320 CPU: 1 PID: 10320 Comm: syz.1.1126 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x24e 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+0x1b2/0x280 lib/crc-itu-t.c:60 udf_finalize_lvid fs/udf/super.c:2054 [inline] udf_close_lvid+0x554/0x9a0 fs/udf/super.c:2122 udf_put_super+0xc8/0x160 fs/udf/super.c:2392 generic_shutdown_super+0x130/0x340 fs/super.c:501 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x982/0x2480 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 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:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7febef39c799 Code: Unable to access opcode bytes at 0x7febef39c76f. RSP: 002b:00007ffc9d2be3b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007febef617da0 RCX: 00007febef39c799 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007febef617da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00007febef617cb0 R11: 0000000000000246 R12: 0000000000068dbb R13: 00007febef61618c R14: 0000000000068bd2 R15: 00007febef616180 The buggy address belongs to the physical page: page:ffffea0001c5f000 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x717c0 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea000142e008 ffffea0001419f08 0000000000000000 raw: 0000000000000001 0000000000000002 00000000ffffff7f 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Movable, gfp_mask 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 10265, tgid 10265 (syz.4.1123), ts 433134987022, free_ts 438651124170 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559 prep_new_page mm/page_alloc.c:2566 [inline] get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5643 __folio_alloc+0xe/0x30 mm/page_alloc.c:5675 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243 shmem_alloc_folio mm/shmem.c:1589 [inline] shmem_alloc_and_acct_folio+0x463/0xbc0 mm/shmem.c:1613 shmem_get_folio_gfp+0x1361/0x3400 mm/shmem.c:1941 shmem_get_folio mm/shmem.c:2072 [inline] shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989 __kernel_write_iter+0x285/0x650 fs/read_write.c:517 dump_emit_page fs/coredump.c:950 [inline] dump_user_range+0x412/0x850 fs/coredump.c:977 elf_core_dump+0x30a6/0x35d0 fs/binfmt_elf.c:2354 do_coredump+0x165b/0x22f0 fs/coredump.c:824 get_signal+0x10aa/0x1350 kernel/signal.c:2857 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1486 [inline] free_pcp_prepare mm/page_alloc.c:1536 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3554 release_pages+0x1fa6/0x2220 mm/swap.c:1035 __pagevec_release+0x6d/0xe0 mm/swap.c:1055 pagevec_release include/linux/pagevec.h:71 [inline] folio_batch_release include/linux/pagevec.h:135 [inline] shmem_undo_range+0x7c2/0x20c0 mm/shmem.c:946 shmem_truncate_range mm/shmem.c:1062 [inline] shmem_evict_inode+0x25b/0xa80 mm/shmem.c:1171 evict+0x4c9/0x8d0 fs/inode.c:705 __dentry_kill+0x431/0x650 fs/dcache.c:611 dentry_kill+0xb8/0x290 fs/dcache.c:-1 dput+0xfa/0x1d0 fs/dcache.c:918 __fput+0x5e0/0x920 fs/file_table.c:328 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x982/0x2480 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 get_signal+0x1272/0x1350 kernel/signal.c:2871 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871 Memory state around the buggy address: ffff8880717bff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880717bff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880717c0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8880717c0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880717c0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================