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 ffff8881adf600a6 by task syz.3.97/6180

CPU: 1 UID: 0 PID: 6180 Comm: syz.3.97 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+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a14d9e04a
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:00007f3a12ff5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f3a12ff5ee0 RCX: 00007f3a14d9e04a
RDX: 0000200000000100 RSI: 0000200000000040 RDI: 00007f3a12ff5ea0
RBP: 0000200000000100 R08: 00007f3a12ff5ee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000040
R13: 00007f3a12ff5ea0 R14: 0000000000009e30 R15: 00002000000000c0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x686 pfn:0x1adf60
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 057ff00000000000 ffffea0006b7cc08 ffffea0006b7eb08 0000000000000000
raw: 0000000000000686 0000000000000001 00000000f0000000 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 6124, tgid 6122 (syz.3.82), ts 86024974177, free_ts 86480883114
 post_alloc_hook+0x1f9/0x250
 get_page_from_freelist+0x24ba/0x2540
 __alloc_frozen_pages_noprof+0x18d/0x380
 alloc_pages_mpol+0x235/0x490
 folio_alloc_mpol_noprof+0x39/0x160
 shmem_alloc_and_add_folio+0x442/0xf80
 shmem_get_folio_gfp+0x5a9/0x1670
 shmem_fault+0x179/0x390
 __do_fault+0x138/0x2a0
 do_pte_missing+0x2093/0x33e0
 handle_mm_fault+0x1bd7/0x3170
 __get_user_pages+0x1683/0x2720
 populate_vma_page_range+0x2be/0x3c0
 __mm_populate+0x25f/0x390
 vm_mmap_pgoff+0x3aa/0x4f0
 do_syscall_64+0x15f/0xf80
page last free pid 6140 tgid 6122 stack trace:
 free_unref_folios+0xcde/0x1420
 folios_put_refs+0xa3d/0xb80
 shmem_undo_range+0x52c/0x1660
 shmem_evict_inode+0x289/0xae0
 evict+0x61e/0xb10
 __dentry_kill+0x1a2/0x690
 finish_dput+0xc9/0x480
 __fput+0x691/0xa60
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x22c0
 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+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8881adf5ff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881adf60000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881adf60080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8881adf60100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881adf60180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
