diff --git a/sys/conf/files b/sys/conf/files
index dc837eb02c0..8c3bdca6190 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -3872,7 +3872,7 @@ kern/subr_mchain.c		optional libmchain
 kern/subr_memdesc.c		standard
 kern/subr_module.c		standard
 kern/subr_msan.c		optional kmsan \
-	compile-with "${NORMAL_C:N-fsanitize*:N-fstack-protector*}"
+	compile-with "${NORMAL_C:N-fsanitize*:N-fno-sanitize*:N-fstack-protector*}"
 kern/subr_msgbuf.c		standard
 kern/subr_param.c		standard
 kern/subr_pcpu.c		standard
diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 4d37cd4156f..158175eb689 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -122,8 +122,11 @@ SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kcsan \
 
 KMSAN_ENABLED!= grep KMSAN opt_global.h || true ; echo
 .if !empty(KMSAN_ENABLED)
+# Disable -fno-sanitize-memory-param-retval until interceptors have been
+# updated to work properly with it.
 SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kmsan \
-		-fsanitize=kernel-memory
+		-fsanitize=kernel-memory \
+		-fno-sanitize-memory-param-retval
 .endif
 
 KUBSAN_ENABLED!=	grep KUBSAN opt_global.h || true ; echo