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 ffff8881af54b8a6 by task syz.7.1119/12101

CPU: 1 UID: 0 PID: 12101 Comm: syz.7.1119 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_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: 0033:0x7f0d36b9f28a
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:00007f0d3799ae58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f0d3799aee0 RCX: 00007f0d36b9f28a
RDX: 0000200000000100 RSI: 0000200000000040 RDI: 00007f0d3799aea0
RBP: 0000200000000100 R08: 00007f0d3799aee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000040
R13: 00007f0d3799aea0 R14: 0000000000009e15 R15: 0000200000000000
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x4c9 pfn:0x1af54b
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 00000000000004c9 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 11881, tgid 11880 (syz.6.1061), ts 584211920030, free_ts 585040250638
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x2503/0x25a0
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x22b/0x390
 folio_alloc_mpol_noprof+0x39/0x70
 shmem_alloc_and_add_folio+0x441/0xf60
 shmem_get_folio_gfp+0x5b2/0x16c0
 shmem_fault+0x179/0x390
 __do_fault+0x138/0x390
 do_pte_missing+0x23b6/0x39a0
 handle_mm_fault+0x1b11/0x3270
 __get_user_pages+0x15f6/0x2970
 populate_vma_page_range+0x2be/0x3c0
 __mm_populate+0x25f/0x390
 vm_mmap_pgoff+0x353/0x4e0
 do_syscall_64+0x170/0xf80
page last free pid 11880 tgid 11880 stack trace:
 free_unref_folios+0xf29/0x1740
 folios_put_refs+0x795/0x8d0
 shmem_undo_range+0x4e6/0x15d0
 shmem_evict_inode+0x280/0xa70
 evict+0x624/0xb50
 __dentry_kill+0x19f/0x5d0
 finish_dput+0xca/0x490
 __fput+0x670/0xa40
 task_work_run+0x1d9/0x270
 do_exit+0x73a/0x2460
 do_group_exit+0x22d/0x2f0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x221a/0x2240
 do_syscall_64+0x170/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8881af54b780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881af54b800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881af54b880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8881af54b900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881af54b980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
