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 ffff8881adaa18a6 by task syz.0.23/5995

CPU: 1 UID: 0 PID: 5995 Comm: syz.0.23 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+0xba/0x230
 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: 0033:0x7f912c99da0a
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:00007f912abede58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f912abedee0 RCX: 00007f912c99da0a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f912abedea0
RBP: 000020000000a000 R08: 00007f912abedee0 R09: 0000000003a04e43
R10: 0000000003a04e43 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f912abedea0 R14: 0000000000009e15 R15: 0000200000000440
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x200000572 pfn:0x1adaa1
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea0006b6a888 ffffea0006b6a048 0000000000000000
raw: 0000000200000572 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 5983, tgid 5981 (syz.1.19), ts 69781531176, free_ts 70008624620
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x24dc/0x2580
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x232/0x4a0
 vma_alloc_folio_noprof+0xea/0x210
 do_pte_missing+0x1656/0x3490
 handle_mm_fault+0x1bec/0x3310
 __get_user_pages+0x165b/0x29d0
 populate_vma_page_range+0x2be/0x3c0
 __mm_populate+0x25f/0x390
 vm_mmap_pgoff+0x3aa/0x4f0
 do_syscall_64+0x14d/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5987 tgid 5981 stack trace:
 free_unref_folios+0xed5/0x16d0
 shrink_folio_list+0x2a0f/0x5290
 reclaim_folio_list+0x100/0x460
 reclaim_pages+0x45b/0x530
 madvise_cold_or_pageout_pte_range+0x1e2d/0x2220
 walk_pgd_range+0x1032/0x1d30
 __walk_page_range+0x14c/0x710
 walk_page_range_vma_unsafe+0x309/0x410
 madvise_vma_behavior+0x2850/0x4300
 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

Memory state around the buggy address:
 ffff8881adaa1780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881adaa1800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881adaa1880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8881adaa1900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881adaa1980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
