hpfs: filesystem error: warning: spare dnodes used, try chkdsk
hpfs: You really don't want any checks? You are crazy...
hpfs: hpfs_map_sector(): read error
hpfs: code page support is disabled
==================================================================
BUG: KASAN: use-after-free in strcmp+0x6b/0xc0 lib/string.c:265
Read of size 1 at addr ffff88804b6818a6 by task syz.4.167/6453

CPU: 0 UID: 0 PID: 6453 Comm: syz.4.167 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 strcmp+0x6b/0xc0 lib/string.c:265
 hpfs_get_ea+0x137/0xeb0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x1a9/0x1060 fs/hpfs/inode.c:63
 hpfs_fill_super+0x127b/0x1fb0 fs/hpfs/super.c:652
 get_tree_bdev_flags+0x436/0x500 fs/super.c:1821
 vfs_get_tree+0x92/0x2a0 fs/super.c:1881
 fc_mount fs/namespace.c:1282 [inline]
 do_new_mount_fc fs/namespace.c:3910 [inline]
 do_new_mount+0x325/0xb00 fs/namespace.c:3986
 do_mount fs/namespace.c:4350 [inline]
 __do_sys_mount fs/namespace.c:4565 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4542
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f40c8da0d8a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f40c9ca5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f40c9ca5ee0 RCX: 00007f40c8da0d8a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f40c9ca5ea0
RBP: 000020000000a000 R08: 00007f40c9ca5ee0 R09: 0000000003a00041
R10: 0000000003a00041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f40c9ca5ea0 R14: 0000000000009e2e R15: 0000200000000040
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x24ca pfn:0x4b681
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 00000000000024ca 0000000000000000 00000000ffffffff 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 6072, tgid 6072 (syz.4.56), ts 119294632266
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x2224/0x2290 mm/page_alloc.c:3940
 __alloc_frozen_pages_noprof+0x1fe/0x410 mm/page_alloc.c:5464
 alloc_pages_mpol+0x21e/0x390 mm/mempolicy.c:2511
 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2530
 shmem_alloc_folio mm/shmem.c:2184 [inline]
 shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:2226
 shmem_get_folio_gfp+0x594/0x1330 mm/shmem.c:2780
 shmem_get_folio mm/shmem.c:2879 [inline]
 shmem_write_begin+0x16c/0x330 mm/shmem.c:3514
 generic_perform_write+0x2d5/0x8e0 mm/filemap.c:4392
 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3689
 __kernel_write_iter+0x44a/0x8f0 fs/read_write.c:621
 dump_write_iter fs/coredump.c:1360 [inline]
 dump_emit_page fs/coredump.c:1533 [inline]
 dump_user_range+0x715/0xca0 fs/coredump.c:1601
 elf_core_dump+0x346a/0x3a70 fs/binfmt_elf.c:2106
 coredump_write fs/coredump.c:1150 [inline]
 do_coredump+0x5ed1/0x6a60 fs/coredump.c:1237
 vfs_coredump+0xac3/0x10c0 fs/coredump.c:1312
 get_signal+0x11d1/0x1430 kernel/signal.c:3098
page last free pid 6072 tgid 6072 ts 131832404320 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1403 [inline]
 free_unref_folios+0xdc6/0x14e0 mm/page_alloc.c:3017
 folios_put_refs+0x9e9/0xb30 mm/folio.c:1039
 folio_batch_release include/linux/folio_batch.h:101 [inline]
 shmem_undo_range+0x55a/0x1730 mm/shmem.c:1377
 shmem_truncate_range mm/shmem.c:1513 [inline]
 shmem_evict_inode+0x240/0xb00 mm/shmem.c:1657
 evict+0x624/0xb50 fs/inode.c:821
 dentry_kill+0x1b9/0x910 fs/dcache.c:856
 finish_dput+0x1a/0x260 fs/dcache.c:1031
 __fput+0x65b/0xa40 fs/file_table.c:520
 task_work_run+0x1d9/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x705/0x2360 kernel/exit.c:980
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123
 get_signal+0x136a/0x1430 kernel/signal.c:3113
 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:101 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline]
 irqentry_exit+0x348/0x9b0 kernel/entry/common.c:152
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595

Memory state around the buggy address:
 ffff88804b681780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804b681800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88804b681880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88804b681900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880
 ffff88804b681980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================