VMALLOC_SIZE
num2 = VMALLOC_SIZE / PGDIR_SIZE;
#define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE)
#define VMALLOC_END (VMALLOC_START + VMALLOC_SIZE)
kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE);
#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)