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 ffff88823fe798a6 by task syz.0.64/5895

CPU: 1 UID: 0 PID: 5895 Comm: syz.0.64 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+0x137/0xeb0
 hpfs_read_inode+0x1a9/0x1060
 hpfs_fill_super+0x125c/0x1fc0
 get_tree_bdev_flags+0x430/0x4f0
 vfs_get_tree+0x92/0x2a0
 do_new_mount+0x319/0xdc0
 __se_sys_mount+0x31d/0x420
 do_syscall_64+0x170/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8040d9f28a
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:00007f8041ba2e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f8041ba2ee0 RCX: 00007f8040d9f28a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f8041ba2ea0
RBP: 000020000000a000 R08: 00007f8041ba2ee0 R09: 0000000003204441
R10: 0000000003204441 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f8041ba2ea0 R14: 0000000000009e15 R15: 0000200000000140
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x200000002 pfn:0x23fe79
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 ffffea0008ff9e88 ffffea0006efe5c8 0000000000000000
raw: 0000000200000002 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 5889, tgid 5889 (syz.2.63), ts 60236510916, free_ts 60548948681
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x2503/0x25a0
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x22b/0x390
 vma_alloc_folio_noprof+0xea/0x210
 do_pte_missing+0x172b/0x39a0
 handle_mm_fault+0x1b11/0x3270
 do_user_addr_fault+0xa4d/0x1340
 exc_page_fault+0x6a/0xc0
 asm_exc_page_fault+0x26/0x30
page last free pid 5890 tgid 5889 stack trace:
 free_unref_folios+0xf29/0x1740
 folios_put_refs+0x795/0x8d0
 free_pages_and_swap_cache+0x525/0x590
 tlb_flush_mmu+0x6d3/0xa30
 unmap_page_range+0x3c70/0x48f0
 unmap_vmas+0x462/0x680
 exit_mmap+0x292/0xa20
 __mmput+0x118/0x420
 exit_mm+0x160/0x210
 do_exit+0x6cd/0x2460
 do_group_exit+0x22d/0x2f0
 get_signal+0x121b/0x12c0
 arch_do_signal_or_restart+0xbb/0x810
 exit_to_user_mode_loop+0xa3/0x5e0
 do_syscall_64+0x357/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88823fe79780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88823fe79800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88823fe79880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88823fe79900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88823fe79980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
