diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 3de2adc0a807..a2883360d07c 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1249,7 +1249,7 @@ static int cpu_cmd(void)
 	unsigned long cpu, first_cpu, last_cpu;
 	int timeout;
 
-	if (!scanhex(&cpu)) {
+	if (!scanhex(&cpu) || cpu >= num_possible_cpus()) {
 		/* print cpus waiting or in xmon */
 		printf("cpus stopped:");
 		last_cpu = first_cpu = NR_CPUS;
@@ -2680,7 +2680,7 @@ static void dump_pacas(void)
 
 	termch = c;	/* Put c back, it wasn't 'a' */
 
-	if (scanhex(&num))
+	if (scanhex(&num) && num < num_possible_cpus())
 		dump_one_paca(num);
 	else
 		dump_one_paca(xmon_owner);
@@ -2777,7 +2777,7 @@ static void dump_xives(void)
 
 	termch = c;	/* Put c back, it wasn't 'a' */
 
-	if (scanhex(&num))
+	if (scanhex(&num) && num < num_possible_cpus())
 		dump_one_xive(num);
 	else
 		dump_one_xive(xmon_owner);