diff --git a/tests/Makefile b/tests/Makefile
index ca12c2bb3ea1cb1cab8724d69a029aab490bb628..a34ef913ffe670a8df90609077d981b4251fa839 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -13,7 +13,7 @@
 CFLAGS=-pthread -Wall -O3 -Werror -Wmissing-prototypes -fopenmp -DNDEBUG
 LDFLAGS=-pthread
 # for debugging, you may use these
-#CFLAGS=-Wall -O0 -g -Werror -Wmissing-prototypes -fopenmp
+#CFLAGS=-Wall -O0 -g -Werror -Wmissing-prototypes -fopenmp -fsanitize=undefined
 
 OBJ=threadpool.o list.o threadpool_lib.o
 
diff --git a/tests/threadpool_test6.py b/tests/threadpool_test6.py
index 4dae290189a98efd14ae6dfc8f8ab72098392035..1c9dde5dffda3d509902f06d005e44aa3995df7e 100755
--- a/tests/threadpool_test6.py
+++ b/tests/threadpool_test6.py
@@ -5,7 +5,7 @@
 
 import sys, subprocess, re, os
 
-valgrind_cmd = ["valgrind", "--leak-check=full", "--suppressions=sigaltstack.suppression", "./threadpool_test6"]
+valgrind_cmd = ["valgrind", "--fair-sched=yes", "--leak-check=full", "--suppressions=sigaltstack.suppression", "./threadpool_test6"]
 
 proc = subprocess.Popen(valgrind_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 stdout, stderr = proc.communicate()