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/0xc0
Read of size 1 at addr ffff8881be5ed078 by task syz.0.561/10820

CPU: 1 UID: 0 PID: 10820 Comm: syz.0.561 Not tainted syzkaller #0 PREEMPT(full) 
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_report+0xca/0x240
 kasan_report+0x118/0x150
 strcmp+0x6f/0xc0
 hpfs_get_ea+0x114/0xdb0
 hpfs_read_inode+0x19d/0x1010
 hpfs_fill_super+0x129d/0x2040
 get_tree_bdev_flags+0x40e/0x4d0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x302/0xa10
 __se_sys_mount+0x313/0x410
 do_syscall_64+0xec/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd4f4990f6a
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:00007fd4f5853e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd4f5853ef0 RCX: 00007fd4f4990f6a
RDX: 0000200000000000 RSI: 0000200000009ec0 RDI: 00007fd4f5853eb0
RBP: 0000200000000000 R08: 00007fd4f5853ef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007fd4f5853eb0 R14: 0000000000009e2f R15: 0000200000000080
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x7f0da471b pfn:0x1be5ed
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea0006f977c8 ffffea0006d1c408 0000000000000000
raw: 00000007f0da471b 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 10793, tgid 10792 (syz.3.557), ts 221359027662, free_ts 221550837812
 post_alloc_hook+0x234/0x290
 get_page_from_freelist+0x24e0/0x2580
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 vma_alloc_folio_noprof+0xe4/0x200
 folio_prealloc+0x30/0x180
 do_pte_missing+0x14e8/0x3330
 handle_mm_fault+0x1b26/0x32b0
 do_user_addr_fault+0xa7c/0x1380
 exc_page_fault+0x71/0xd0
 asm_exc_page_fault+0x26/0x30
page last free pid 10793 tgid 10792 stack trace:
 free_unref_folios+0xdb3/0x14f0
 folios_put_refs+0x584/0x670
 free_pages_and_swap_cache+0x277/0x520
 tlb_flush_mmu+0x3a0/0x680
 tlb_finish_mmu+0xc3/0x1d0
 vms_clear_ptes+0x42b/0x530
 vms_complete_munmap_vmas+0x206/0x8a0
 do_vmi_align_munmap+0x364/0x440
 do_vmi_munmap+0x253/0x2e0
 __vm_munmap+0x207/0x380
 __x64_sys_munmap+0x60/0x70
 do_syscall_64+0xec/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8881be5ecf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881be5ecf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881be5ed000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                                ^
 ffff8881be5ed080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881be5ed100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
