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 ffff88804f8a0003 by task syz.1.71/4836

CPU: 0 PID: 4836 Comm: syz.1.71 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
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+0x134/0xda0 fs/hpfs/ea.c:139
 hpfs_read_inode+0x1a6/0x1050 fs/hpfs/inode.c:63
 hpfs_fill_super+0x12ee/0x1f30 fs/hpfs/super.c:712
 mount_bdev+0x28a/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+0x247/0xa40 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: 0033:0x7fba5819f10a
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:00007fba59016e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fba59016ee0 RCX: 00007fba5819f10a
RDX: 000020000000a000 RSI: 0000200000009ec0 RDI: 00007fba59016ea0
RBP: 000020000000a000 R08: 00007fba59016ee0 R09: 0000000003200041
R10: 0000000003200041 R11: 0000000000000246 R12: 0000200000009ec0
R13: 00007fba59016ea0 R14: 0000000000009e15 R15: 00002000000000c0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00013e2800 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x4f8a0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00013fb408 ffffea000142f008 0000000000000000
raw: 0000000000000001 0000000000000003 00000000ffffff7f 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 4809, tgid 4759 (syz.3.65), ts 118038294890, free_ts 118562515828
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 __folio_alloc+0xe/0x30 mm/page_alloc.c:5690
 vma_alloc_folio+0x499/0x900 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1589 [inline]
 shmem_alloc_and_acct_folio+0x463/0xbd0 mm/shmem.c:1613
 shmem_get_folio_gfp+0x1439/0x35e0 mm/shmem.c:1941
 shmem_fault+0x1b6/0x790 mm/shmem.c:2156
 __do_fault+0x13b/0x4e0 mm/memory.c:4278
 do_read_fault mm/memory.c:4629 [inline]
 do_fault mm/memory.c:4758 [inline]
 handle_pte_fault mm/memory.c:5029 [inline]
 __handle_mm_fault mm/memory.c:5171 [inline]
 handle_mm_fault+0x2610/0x3d40 mm/memory.c:5292
 faultin_page mm/gup.c:1026 [inline]
 __get_user_pages+0x40d/0xec0 mm/gup.c:1250
 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607
 __mm_populate+0x25c/0x380 mm/gup.c:1721
 mm_populate include/linux/mm.h:2891 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:525
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1487 [inline]
 free_pcp_prepare mm/page_alloc.c:1537 [inline]
 free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3555
 release_pages+0x20d1/0x2340 mm/swap.c:1035
 __pagevec_release+0x6d/0xe0 mm/swap.c:1055
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x808/0x21d0 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x225/0x9f0 mm/shmem.c:1171
 evict+0x4b6/0x8b0 fs/inode.c:705
 __dentry_kill+0x412/0x630 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfa/0x1d0 fs/dcache.c:918
 __fput+0x597/0x8b0 fs/file_table.c:328
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x9d5/0x2570 kernel/exit.c:881
 do_group_exit+0x229/0x2e0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76

Memory state around the buggy address:
 ffff88804f89ff00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804f89ff80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804f8a0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88804f8a0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88804f8a0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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