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+0x6f/0xc0
Read of size 1 at addr ffff88803bd57002 by task syz.2.18/6037

CPU: 1 UID: 0 PID: 6037 Comm: syz.2.18 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+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 strcmp+0x6f/0xc0
 hpfs_get_ea+0x114/0xdb0
 hpfs_read_inode+0x19d/0x1010
 hpfs_fill_super+0x129d/0x2040
 get_tree_bdev_flags+0x40e/0x4d0
 vfs_get_tree+0x92/0x2b0
 do_new_mount+0x302/0xa10
 __se_sys_mount+0x313/0x410
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f255899038a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2559889e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2559889ef0 RCX: 00007f255899038a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f2559889eb0
RBP: 000020000000a000 R08: 00007f2559889ef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f2559889eb0 R14: 0000000000009e2c R15: 0000200000000000
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x1f pfn:0x3bd57
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0000ef5608 ffffea0000ef5a08 0000000000000000
raw: 000000000000001f 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x41c40(GFP_NOFS|__GFP_WRITE|__GFP_COMP), pid 6019, tgid 6018 (syz.2.14), ts 67196311565, free_ts 67482804112
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 alloc_pages_noprof+0xa9/0x190
 folio_alloc_noprof+0x1e/0x30
 filemap_alloc_folio_noprof+0xdf/0x470
 __filemap_get_folio+0x3f2/0xaf0
 f2fs_write_begin+0x320/0x2290
 generic_perform_write+0x2c5/0x900
 f2fs_file_write_iter+0x1ec9/0x2410
 vfs_write+0x5c9/0xb30
 __x64_sys_pwrite64+0x193/0x220
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5846 tgid 5846 stack trace:
 free_unref_folios+0xdb3/0x14f0
 folios_put_refs+0x584/0x670
 truncate_inode_pages_range+0x346/0xda0
 f2fs_evict_inode+0x2a2/0x1b60
 evict+0x504/0x9c0
 evict_inodes+0x466/0x6d0
 generic_shutdown_super+0x9a/0x2c0
 kill_block_super+0x44/0x90
 kill_f2fs_super+0x399/0x6d0
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x130
 do_syscall_64+0x2bd/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803bd56f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88803bd56f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88803bd57000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88803bd57080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88803bd57100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
