diff --git a/src/jemalloc.c b/src/jemalloc.c
index 0ca400e3..b21b2d9d 100644
--- a/src/jemalloc.c
+++ b/src/jemalloc.c
@@ -1458,6 +1458,10 @@ malloc_conf_init_helper(sc_data_t *sc_data, unsigned bin_shard_sizes[SC_NBINS],
 					   CONF_CHECK_MIN, CONF_CHECK_MAX,
 					   true);
 			if (CONF_MATCH("slab_sizes")) {
+				if (CONF_MATCH_VALUE("default")) {
+					sc_data_init(sc_data);
+					CONF_CONTINUE;
+				}
 				bool err;
 				const char *slab_size_segment_cur = v;
 				size_t vlen_left = vlen;
diff --git a/src/sc.c b/src/sc.c
index 1474eacc..37683ff4 100644
--- a/src/sc.c
+++ b/src/sc.c
@@ -257,8 +257,6 @@ size_classes(
 
 void
 sc_data_init(sc_data_t *sc_data) {
-	assert(!sc_data->initialized);
-
 	size_classes(sc_data, LG_SIZEOF_PTR, LG_QUANTUM, SC_LG_TINY_MIN,
 	    SC_LG_MAX_LOOKUP, LG_PAGE, SC_LG_NGROUP);