Arm64 Linux 4.19内核空间地址PTE查找问题求助

我正在为研究开发一款Linux 4.19（ArmV8）内核模块，需要查找内核空间地址的PTE。以下是根据建议优化后的代码（使用READ_ONCE优化页表项读取，并调整了变量命名）：

pte_t *lookup_address_arm64(unsigned long addr, unsigned int *level)
{
    pgd_t *pgdp;
    pud_t *pudp, pud;
    pmd_t *pmdp, pmd;

    *level = 0;

    pgd_t *pgd_base;
    unsigned long phys_addr;
    // 读取TTBR1_EL1获取PGD，尝试过pgd_offset_k但init_mm未定义
    phys_addr = read_sysreg(ttbr1_el1) & ((1UL << 48) - 2); // 获取基地址
    
    // 转换为虚拟地址
    pgd_base = (pgd_t *)phys_to_virt(phys_addr);

    pgdp = pgd_offset_raw(pgd_base, addr);
    
    if (pgd_none(READ_ONCE(*pgdp)))
        return NULL;

    pudp = pud_offset(pgdp, addr);
    pud = READ_ONCE(*pudp);
    
    if (pud_none(pud))
        return NULL;
    *level = 3;
    
    if (pud_sect(pud))
        return (pte_t *)pudp;

    pmdp = pmd_offset(pudp, addr);
    pmd = READ_ONCE(*pmdp);
    
    if (pmd_none(pmd))
        return NULL;
    *level = 2;
    if (pmd_sect(pmd))
        return (pte_t *)pmdp;

    *level = 1;
    return pte_offset_kernel(pmdp, addr);
}

当前代码未触发内核panic，但会在return (pte_t *)pudp;处返回。我要查找的地址位于物理内存直接映射区域，代码返回是因为检测到pud为大页PTE，但我已经通过在.config中取消设置CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS禁用了大页，且通过以下命令验证：

# cat /proc/meminfo | grep -i huge

HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:               0 kB

调试时打印的关键变量值：

[   15.990883] [look_up_addr] addr at 0xffff800040000000 pgd_base at 0xffff8000017f8000
[   15.993070] [look_up_addr] addr at 0xffff800040000000 pgdp at 0xffff8000017f8800
[   15.993835] [look_up_addr] addr at 0xffff800040000000 pgd val = 0xbdff7803
[   15.994384] [look_up_addr] addr at 0xffff800040000000 pudp at 0xffff80007dff7008
[   15.994812] [look_up_addr] addr at 0xffff800040000000 pud val = 0xe8000080000f11

此前已解决的内核panic信息：

[ 20.339178] Unable to handle kernel paging request at virtual address ffffc17f40000800
[ 20.342033] Mem abort info:
[ 20.342592] ESR = 0x96000004
[ 20.343163] Exception class = DABT (current EL), IL = 32 bits
[ 20.344075] SET = 0, FnV = 0
[ 20.346614] EA = 0, S1PTW = 0
[ 20.347305] Data abort info:
[ 20.347707] ISV = 0, ISS = 0x00000004
[ 20.348805] CM = 0, WnR = 0
[ 20.353096] swapper pgtable: 4k pages, 48-bit VAs, pgdp = 00000000a2e904bd
[ 20.354361] [ffffc17f40000800] pgd=0000000000000000
[ 20.355638] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 20.357312] Dumping ftrace buffer:
[ 20.358719] (ftrace buffer empty)

内容的提问来源于stack exchange，提问作者JamesMcgill