void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
{
	/* entry 0 MUST be WB (hardwired to speed up translations) */
	BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);

	__cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
	__pte2cachemode_tbl[entry] = cache;
}

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.