diff --git a/src/jloptions.c b/src/jloptions.c
index 50ef415bc0bac..2eeb0eb03ee35 100644
--- a/src/jloptions.c
+++ b/src/jloptions.c
@@ -725,9 +725,11 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
                 }
                 jl_options.nthreads = nthreads + nthreadsi;
             }
+            assert(jl_options.nthreadpools == 1 || jl_options.nthreadpools == 2);
             int16_t *ntpp = (int16_t *)malloc_s(jl_options.nthreadpools * sizeof(int16_t));
             ntpp[0] = (int16_t)nthreads;
-            ntpp[1] = (int16_t)nthreadsi;
+            if (jl_options.nthreadpools == 2)
+                ntpp[1] = (int16_t)nthreadsi;
             jl_options.nthreads_per_pool = ntpp;
             break;
         }