diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 9d9e32027ec7..056963adcb2d 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -100,7 +100,8 @@ SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kasan \
 		-mllvm -asan-instrument-dynamic-allocas=true \
 		-mllvm -asan-globals=true \
 		-mllvm -asan-use-after-scope=true \
-		-mllvm -asan-instrumentation-with-call-threshold=0
+		-mllvm -asan-instrumentation-with-call-threshold=0 \
+		-mllvm -asan-instrument-byval=false
 .endif
 
 KCSAN_ENABLED!=	grep KCSAN opt_global.h || true ; echo