numa: Reject duplicate node IDs

The same nodeid shouldn't appear multiple times in the command-line.

In addition to detecting command-line mistakes, this will fix a bug
where nb_numa_nodes may become larger than MAX_NODES (and cause
out-of-bounds access on the numa_info array).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
diff --git a/numa.c b/numa.c
index db10f95..c254127 100644
--- a/numa.c
+++ b/numa.c
@@ -62,6 +62,11 @@
         return;
     }
 
+    if (numa_info[nodenr].present) {
+        error_setg(errp, "Duplicate NUMA nodeid: %" PRIu16, nodenr);
+        return;
+    }
+
     for (cpus = node->cpus; cpus; cpus = cpus->next) {
         if (cpus->value > MAX_CPUMASK_BITS) {
             error_setg(errp, "CPU number %" PRIu16 " is bigger than %d",