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+0x67/0xb0 lib/string.c:361
Read of size 1 at addr ffff888055f75fa6 by task syz.0.3193/12013

CPU: 1 PID: 12013 Comm: syz.0.3193 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 strcmp+0x67/0xb0 lib/string.c:361
 hpfs_get_ea+0x132/0xde0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x1a3/0x1050 fs/hpfs/inode.c:63
 hpfs_fill_super+0x135a/0x1fd0 fs/hpfs/super.c:712
 mount_bdev+0x287/0x3c0 fs/super.c:1443
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x24a/0xa40 fs/namespace.c:3078
 do_mount fs/namespace.c:3421 [inline]
 __do_sys_mount fs/namespace.c:3629 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9460f9da0a
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:00007f9461e1de58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f9461e1dee0 RCX: 00007f9460f9da0a
RDX: 000020000000a000 RSI: 0000200000000000 RDI: 00007f9461e1dea0
RBP: 000020000000a000 R08: 00007f9461e1dee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000000000
R13: 00007f9461e1dea0 R14: 0000000000009e18 R15: 0000200000000080
 </TASK>

The buggy address belongs to the physical page:
page:ffffea000157dd40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x55f75
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ab4188 ffffea00013d1888 0000000000000000
raw: 0000000000000001 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 12006, tgid 12006 (syz.2.3184), ts 293564228505, free_ts 293665599588
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
 prep_new_page mm/page_alloc.c:2566 [inline]
 get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5657
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5689
 vma_alloc_folio+0x4a3/0x900 mm/mempolicy.c:2243
 alloc_page_vma include/linux/gfp.h:284 [inline]
 wp_page_copy+0x2bd/0x1680 mm/memory.c:3151
 handle_pte_fault mm/memory.c:5047 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x1d19/0x3ee0 mm/memory.c:5292
 do_user_addr_fault+0x51f/0xb10 arch/x86/mm/fault.c:1338
 handle_page_fault arch/x86/mm/fault.c:1429 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1482
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:608
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1486 [inline]
 free_pcp_prepare mm/page_alloc.c:1536 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3554
 release_pages+0x1fa6/0x2220 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0x105/0x220 mm/mmu_gather.c:261
 tlb_finish_mmu+0xbd/0x1c0 mm/mmu_gather.c:361
 exit_mmap+0x384/0x960 mm/mmap.c:3262
 __mmput+0x118/0x3c0 kernel/fork.c:1205
 exit_mm+0x1fe/0x2d0 kernel/exit.c:565
 do_exit+0x905/0x2480 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82

Memory state around the buggy address:
 ffff888055f75e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888055f75f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888055f75f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff888055f76000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888055f76080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================