diff --git a/src/network/tc/htb.c b/src/network/tc/htb.c
index 5c85e1a76d..37c2b9529c 100644
--- a/src/network/tc/htb.c
+++ b/src/network/tc/htb.c
@@ -470,6 +470,8 @@ static int hierarchy_token_bucket_class_verify(TClass *tclass) {
         if (r < 0)
                 return log_error_errno(r, "Failed to read /proc/net/psched: %m");
 
+        /* Kernel would never hand us 0 Hz. */
+        assert(hz > 0);
         if (htb->buffer == 0)
                 htb->buffer = htb->rate / hz + htb->mtu;
         if (htb->ceil_buffer == 0)