static int policy_node(gfp_t gfp, struct mempolicy *policy,
								int nd)
{
	if (policy->mode == MPOL_PREFERRED && !(policy->flags & MPOL_F_LOCAL))
		nd = policy->v.preferred_node;
	else {
		/*
		 * __GFP_THISNODE shouldn't even be used with the bind policy
		 * because we might easily break the expectation to stay on the
		 * requested node and not break the policy.
		 */
		WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
	}

	return nd;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.