diff --git a/lib/libc/gen/arc4random.c b/lib/libc/gen/arc4random.c
index 0fa3dff75cc9..becc17bc2711 100644
--- a/lib/libc/gen/arc4random.c
+++ b/lib/libc/gen/arc4random.c
@@ -144,8 +144,15 @@ arc4_stir(void)
 		arc4_init();
 		rs_initialized = 1;
 	}
-	if (arc4_sysctl(rdat, KEYSIZE) != KEYSIZE)
-		abort(); /* Random sysctl cannot fail. */
+	if (arc4_sysctl(rdat, KEYSIZE) != KEYSIZE) {
+		/*
+		 * The sysctl cannot fail. If it does fail on some FreeBSD
+		 * derivative or after some future change, just abort so that
+		 * the problem will be found and fixed. abort is not normally
+		 * suitable for a library but makes sense here.
+		 */
+		abort();
+	}
 
 	arc4_addrandom(rdat, KEYSIZE);
 
diff --git a/lib/libc/stdlib/random.c b/lib/libc/stdlib/random.c
index f096aecb8335..48b120578698 100644
--- a/lib/libc/stdlib/random.c
+++ b/lib/libc/stdlib/random.c
@@ -279,8 +279,15 @@ srandomdev(void)
 
 	mib[0] = CTL_KERN;
 	mib[1] = KERN_ARND;
-	if (sysctl(mib, 2, state, &len, NULL, 0) == -1 || len != expected)
+	if (sysctl(mib, 2, state, &len, NULL, 0) == -1 || len != expected) {
+		/*
+		 * The sysctl cannot fail. If it does fail on some FreeBSD
+		 * derivative or after some future change, just abort so that
+		 * the problem will be found and fixed. abort is not normally
+		 * suitable for a library but makes sense here.
+		 */
 		abort();
+	}
 
 	if (rand_type != TYPE_0) {
 		fptr = &state[rand_sep];