diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 31614f7c22d6..eae657b877cf 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -833,7 +833,7 @@ cpu_idle(int busy)
 	/* Call main idle method. */
 	cpu_idle_fn(sbt);
 
-	/* Switch timers mack into active mode. */
+	/* Switch timers back into active mode. */
 	if (!busy) {
 		cpu_activeclock();
 		critical_exit();
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 4f001a585101..d43abbf512ac 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -1416,7 +1416,7 @@ cpu_idle(int busy)
 	/* Call main idle method. */
 	cpu_idle_fn(sbt);
 
-	/* Switch timers mack into active mode. */
+	/* Switch timers back into active mode. */
 	if (!busy) {
 		cpu_activeclock();
 		critical_exit();
diff --git a/sys/pc98/pc98/machdep.c b/sys/pc98/pc98/machdep.c
index aec04c04fce3..0146cf32c192 100644
--- a/sys/pc98/pc98/machdep.c
+++ b/sys/pc98/pc98/machdep.c
@@ -1228,7 +1228,7 @@ cpu_idle(int busy)
 	/* Call main idle method. */
 	cpu_idle_fn(sbt);
 
-	/* Switch timers mack into active mode. */
+	/* Switch timers back into active mode. */
 	if (!busy) {
 		cpu_activeclock();
 		critical_exit();