hpfs: filesystem error: improperly stopped
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+0x6f/0xb0 lib/string.c:288
Read of size 1 at addr ffff8880834e98a6 by task syz.7.2484/19391

CPU: 1 PID: 19391 Comm: syz.7.2484 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 strcmp+0x6f/0xb0 lib/string.c:288
 hpfs_get_ea+0x115/0xda0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x19e/0x1010 fs/hpfs/inode.c:63
 hpfs_fill_super+0x12d5/0x1ec0 fs/hpfs/super.c:712
 mount_bdev+0x22b/0x2d0 fs/super.c:1643
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3377
 do_mount fs/namespace.c:3717 [inline]
 __do_sys_mount fs/namespace.c:3926 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3903
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0880f9038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0881d39e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0881d39ef0 RCX: 00007f0880f9038a
RDX: 000020000000a000 RSI: 0000200000000000 RDI: 00007f0881d39eb0
RBP: 000020000000a000 R08: 00007f0881d39ef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f0881d39eb0 R14: 0000000000009e15 R15: 0000200000000040
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00020d3a40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x834e9
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 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 19345, tgid 19344 (syz.7.2476), ts 1460495943199, free_ts 1462634346254
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 __folio_alloc+0x10/0x20 mm/page_alloc.c:4489
 vma_alloc_folio+0x47a/0x8f0 mm/mempolicy.c:2242
 shmem_alloc_folio+0x179/0x230 mm/shmem.c:1680
 shmem_alloc_and_acct_folio+0x189/0x630 mm/shmem.c:1705
 shmem_get_folio_gfp+0xcde/0x2ac0 mm/shmem.c:2042
 shmem_get_folio mm/shmem.c:2165 [inline]
 shmem_write_begin+0xf2/0x420 mm/shmem.c:2707
 generic_perform_write+0x2fb/0x5b0 mm/filemap.c:4016
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:2884
 call_write_iter include/linux/fs.h:2018 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x43b/0x940 fs/read_write.c:584
 ksys_write+0x147/0x250 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 __folio_batch_release+0x71/0xe0 mm/swap.c:1042
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x5d0/0x1a40 mm/shmem.c:1027
 shmem_truncate_range mm/shmem.c:1136 [inline]
 shmem_evict_inode+0x273/0xa70 mm/shmem.c:1265
 evict+0x486/0x870 fs/inode.c:705
 __dentry_kill+0x431/0x650 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfe/0x1e0 fs/dcache.c:918
 __fput+0x5e5/0x970 fs/file_table.c:392
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 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+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff8880834e9780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880834e9800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880834e9880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8880834e9900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880834e9980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================