diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f14d1b18a74f..2453229ba15a 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1160,7 +1160,7 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
 	unsigned long randmask2 = randmask1 >> 3;
 
 	WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
-	/* Most of the time lots of bits, half the time only one bit. */
+	/* Mostly only one bit (need preemption!), sometimes lots of bits. */
 	if (!(randmask1 & 0x7))
 		mask = mask & randmask2;
 	else