diff --git a/sys/libkern/bcopy.c b/sys/libkern/bcopy.c
--- a/sys/libkern/bcopy.c
+++ b/sys/libkern/bcopy.c
@@ -42,6 +42,19 @@
 #undef memcpy
 #undef memmove
 
+#if defined(KASAN) || defined(KCSAN)
+void *
+memcpy(void *dst, const void *src, size_t len)
+{
+	return (SAN_INTERCEPTOR(memcpy)(dst, src, len));
+}
+
+void *
+memmove(void *dst, const void *src, size_t len)
+{
+	return (SAN_INTERCEPTOR(memmove)(dst, src, len));
+}
+#else /* !KASAN && !KCSAN */
 /*
  * sizeof(word) MUST BE A POWER OF TWO
  * SO THAT wmask BELOW IS ALL ONES
@@ -135,3 +148,4 @@
 }
 
 __strong_reference(memcpy, memmove);
+#endif /* KASAN || KCSAN */
diff --git a/sys/libkern/memcmp.c b/sys/libkern/memcmp.c
--- a/sys/libkern/memcmp.c
+++ b/sys/libkern/memcmp.c
@@ -41,6 +41,9 @@
 int
 (memcmp)(const void *s1, const void *s2, size_t n)
 {
+#if defined(KASAN) || defined(KCSAN)
+	return (SAN_INTERCEPTOR(memcmp)(s1, s2, n));
+#else
 	if (n != 0) {
 		const unsigned char *p1 = s1, *p2 = s2;
 
@@ -50,4 +53,5 @@
 		} while (--n != 0);
 	}
 	return (0);
+#endif
 }
diff --git a/sys/libkern/memset.c b/sys/libkern/memset.c
--- a/sys/libkern/memset.c
+++ b/sys/libkern/memset.c
@@ -33,9 +33,13 @@
 void *
 (memset)(void *b, int c, size_t len)
 {
+#if defined(KASAN) || defined(KCSAN)
+	return (SAN_INTERCEPTOR(memset)(b, c, len));
+#else
 	char *bb;
 
 	for (bb = (char *)b; len--; )
 		*bb++ = c;
 	return (b);
+#endif
 }
diff --git a/sys/libkern/strcmp.c b/sys/libkern/strcmp.c
--- a/sys/libkern/strcmp.c
+++ b/sys/libkern/strcmp.c
@@ -41,8 +41,12 @@
 int
 (strcmp)(const char *s1, const char *s2)
 {
+#if defined(KASAN) || defined(KCSAN)
+	return (SAN_INTERCEPTOR(strcmp)(s1, s2));
+#else
 	while (*s1 == *s2++)
 		if (*s1++ == '\0')
 			return (0);
 	return (*(const unsigned char *)s1 - *(const unsigned char *)(s2 - 1));
+#endif
 }
diff --git a/sys/libkern/strcpy.c b/sys/libkern/strcpy.c
--- a/sys/libkern/strcpy.c
+++ b/sys/libkern/strcpy.c
@@ -35,8 +35,12 @@
 char *
 (strcpy)(char * __restrict to, const char * __restrict from)
 {
+#if defined(KASAN) || defined(KCSAN)
+	return (SAN_INTERCEPTOR(strcpy)(to, from));
+#else
 	char *save = to;
 
 	for (; (*to = *from) != 0; ++from, ++to);
 	return(save);
+#endif
 }
diff --git a/sys/libkern/strlen.c b/sys/libkern/strlen.c
--- a/sys/libkern/strlen.c
+++ b/sys/libkern/strlen.c
@@ -29,6 +29,13 @@
 #include <sys/libkern.h>
 #include <sys/limits.h>
 
+#if defined(KASAN) || defined(KCSAN)
+size_t
+(strlen)(const char *str)
+{
+	return (SAN_INTERCEPTOR(strlen)(str));
+}
+#else /* !KASAN && !KCSAN */
 /*
  * Portable strlen() for 32-bit and 64-bit systems.
  *
@@ -119,3 +126,4 @@
 	/* NOTREACHED */
 	return (0);
 }
+#endif /* KASAN || KCSAN */