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 ffff88819a8b08a6 by task syz.2.3788/4086

CPU: 1 UID: 0 PID: 4086 Comm: syz.2.3788 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: 0033:0x7f380bf9e04a
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:00007f380cdd5e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f380cdd5ee0 RCX: 00007f380bf9e04a
RDX: 0000200000000000 RSI: 0000200000009ec0 RDI: 00007f380cdd5ea0
RBP: 0000200000000000 R08: 00007f380cdd5ee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f380cdd5ea0 R14: 0000000000009e2f R15: 00002000000003c0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1b7a pfn:0x19a8b0
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 057ff00000000000 ffffea000694a008 ffffea000697ec08 0000000000000000
raw: 0000000000001b7a 0000000000000004 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 3467, tgid 3452 (syz.4.3718), ts 687161541447, free_ts 687913408283
 post_alloc_hook+0x231/0x280
 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_fallocate+0x96f/0xec0
 vfs_fallocate+0x669/0x7e0
 __x64_sys_fallocate+0xc0/0x110
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 3467 tgid 3452 stack trace:
 free_unref_folios+0xcec/0x1480
 folios_put_refs+0x9ff/0xb40
 shmem_undo_range+0x52c/0x1660
 shmem_fallocate+0xdb8/0xec0
 vfs_fallocate+0x669/0x7e0
 __x64_sys_fallocate+0xc0/0x110
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88819a8b0780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819a8b0800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88819a8b0880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff88819a8b0900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819a8b0980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
