hpfs: hpfs_map_sector(): read error
hpfs: code page support is disabled
==================================================================
BUG: KASAN: use-after-free in strcmp+0x6f/0xc0 lib/string.c:283
Read of size 1 at addr ffff8880471e814e by task syz.3.49/6209

CPU: 0 UID: 0 PID: 6209 Comm: syz.3.49 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 strcmp+0x6f/0xc0 lib/string.c:283
 hpfs_get_ea+0x114/0xdb0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x19d/0x1010 fs/hpfs/inode.c:63
 hpfs_fill_super+0x129d/0x2040 fs/hpfs/super.c:654
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1274 [inline]
 do_new_mount_fc fs/namespace.c:3726 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3802
 do_mount fs/namespace.c:4125 [inline]
 __do_sys_mount fs/namespace.c:4324 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4301
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8ea1d9034a
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:00007f8ea2c2be68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f8ea2c2bef0 RCX: 00007f8ea1d9034a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007f8ea2c2beb0
RBP: 000020000000a000 R08: 00007f8ea2c2bef0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007f8ea2c2beb0 R14: 0000000000009e15 R15: 0000200000000000
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x200000cdc pfn:0x471e8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00011c7a48 ffffea00011c81c8 0000000000000000
raw: 0000000200000cdc 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 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|__GFP_COMP), pid 6223, tgid 6202 (syz.4.47), ts 114728072634, free_ts 114888094674
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
 prep_new_page mm/page_alloc.c:1858 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3869
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5159
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
 folio_alloc_mpol_noprof mm/mempolicy.c:2435 [inline]
 vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2470
 folio_prealloc+0x30/0x180 mm/memory.c:-1
 wp_page_copy mm/memory.c:3684 [inline]
 do_wp_page+0x1231/0x5800 mm/memory.c:4145
 handle_pte_fault mm/memory.c:6203 [inline]
 __handle_mm_fault+0x102e/0x5440 mm/memory.c:6330
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6499
 do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
page last free pid 6223 tgid 6202 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963
 folios_put_refs+0x584/0x670 mm/swap.c:1002
 free_pages_and_swap_cache+0x277/0x520 mm/swap_state.c:355
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
 tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
 zap_pte_range mm/memory.c:1895 [inline]
 zap_pmd_range mm/memory.c:1948 [inline]
 zap_pud_range mm/memory.c:1977 [inline]
 zap_p4d_range mm/memory.c:1998 [inline]
 unmap_page_range+0x3b37/0x4370 mm/memory.c:2019
 unmap_single_vma mm/memory.c:2062 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:2106
 exit_mmap+0x240/0xb40 mm/mmap.c:1280
 __mmput+0x118/0x430 kernel/fork.c:1148
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:954
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880471e8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880471e8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880471e8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8880471e8180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880471e8200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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