The "cpu" variable comes from the sscanf() so Smatch marks it as
untrusted data. We can't pass a higher value than "nr_cpu_ids" to
cpu_possible() or it results in an out of bounds access.
Fixes: d68d82afd4c8 ("xen: implement CPU hotplugging") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>