CVE-2024-26712

In the Linux kernel, the following vulnerability has been resolved:
powerpc/kasan: Fix addr error caused by page alignment In
kasan_init_region, when k_start is not page aligned, at the begin of for
loop, k_cur = k_start & PAGE_MASK is less than k_start, and then va = block + k_cur - k_start is less than block, the addr va is invalid,
because the memory address space from va to block is not alloced by
memblock_alloc, which will not be reserved by memblock_reserve later, it
will be used by other places. As a result, memory overwriting occurs. for
example: int __init __weak kasan_init_region(void start, size_t size) {
[…] / if say block(dcd97000) k_start(feef7400) k_end(feeff3fe) / block
= memblock_alloc(k_end - k_start, PAGE_SIZE); […] for (k_cur = k_start &
PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) { / at the begin of for loop

• block(dcd97000) va(dcd96c00) k_cur(feef7000) k_start(feef7400) *
  va(dcd96c00) is less than block(dcd97000), va is invalid */ void *va =
  block + k_cur - k_start; […] } […] } Therefore, page alignment is
  performed on k_start before memblock_alloc() to ensure the validity of the
  VA address.