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
Read of size 1 at addr ffff88802a6058a6 by task syz.5.1043/10432

CPU: 0 UID: 0 PID: 10432 Comm: syz.5.1043 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_address_description+0x55/0x1e0
 print_report+0x58/0x70
 kasan_report+0x117/0x150
 strcmp+0x6b/0xc0
 hpfs_get_ea+0x134/0xee0
 hpfs_read_inode+0x1a6/0x1050
 hpfs_fill_super+0x123d/0x1fa0
 get_tree_bdev_flags+0x431/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x341/0xd30
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4449f9da0a
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:00007f444ae34e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f444ae34ee0 RCX: 00007f4449f9da0a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f444ae34ea0
RBP: 000020000000a000 R08: 00007f444ae34ee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f444ae34ea0 R14: 0000000000009e15 R15: 0000200000000280
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a605
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 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 9, migratetype Movable, gfp_mask 0x1c24ca(GFP_TRANSHUGE), pid 10384, tgid 10377 (syz.4.1030), ts 260277188087, free_ts 260514652332
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x2418/0x24b0
 __alloc_frozen_pages_noprof+0x233/0x3d0
 __alloc_pages_noprof+0x10/0x100
 __folio_alloc_noprof+0x18/0x120
 alloc_charge_folio+0x3c5/0x930
 collapse_scan_file+0x13a5/0x5100
 collapse_single_pmd+0x22b/0x4510
 madvise_collapse+0x34c/0x820
 madvise_vma_behavior+0x10d9/0x43d0
 madvise_walk_vmas+0x573/0xae0
 madvise_do_behavior+0x386/0x540
 do_madvise+0x1fa/0x2e0
 __x64_sys_madvise+0xa6/0xc0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 10382 tgid 10377 stack trace:
 free_unref_folios+0xcec/0x1480
 folios_put_refs+0x9ff/0xb40
 shmem_undo_range+0x52c/0x1660
 shmem_evict_inode+0x240/0x9e0
 evict+0x61e/0xb10
 __dentry_kill+0x1a2/0x5e0
 finish_dput+0xc9/0x480
 __fput+0x691/0xa70
 task_work_run+0x1d9/0x270
 do_exit+0x926/0x2490
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x830
 exit_to_user_mode_loop+0x86/0x480
 do_syscall_64+0x32d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802a605780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a605800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88802a605880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88802a605900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88802a605980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
