diff --git a/hypervisor/lib/mem_mgt.c b/hypervisor/lib/mem_mgt.c
index 21841b234..950532a6d 100644
--- a/hypervisor/lib/mem_mgt.c
+++ b/hypervisor/lib/mem_mgt.c
@@ -266,7 +266,8 @@ void *malloc(unsigned int num_bytes)
 	}
 
 	/* Check if memory allocation is successful */
-	ASSERT(memory != NULL, "");
+	if (memory == NULL)
+		pr_err("%s: failed to alloc 0x%x Bytes", __func__, num_bytes);
 
 	/* Return memory pointer to caller */
 	return memory;
@@ -280,7 +281,8 @@ void *alloc_pages(unsigned int page_num)
 	memory = allocate_mem(&Paging_Memory_Pool, page_num * CPU_PAGE_SIZE);
 
 	/* Check if memory allocation is successful */
-	ASSERT(memory != NULL, "");
+	if (memory == NULL)
+		pr_err("%s: failed to alloc %d pages", __func__, page_num);
 
 	return memory;
 }
diff --git a/hypervisor/lib/memcpy.c b/hypervisor/lib/memcpy.c
index 1fa00bd5a..fed1d2ff8 100644
--- a/hypervisor/lib/memcpy.c
+++ b/hypervisor/lib/memcpy.c
@@ -54,7 +54,8 @@
  *
  *   OUTPUTS
  *
- *       void *             pointer to destination address
+ *       void *             pointer to destination address if successful,
+ * 			    or else return null.
  *
  ***********************************************************************/
 void *memcpy_s(void *d, size_t dmax, const void *s, size_t slen)
@@ -63,17 +64,21 @@ void *memcpy_s(void *d, size_t dmax, const void *s, size_t slen)
 	uint8_t *dest8;
 	uint8_t *src8;
 
+	if (slen == 0 || dmax == 0 || dmax < slen) {
+		pr_err("%s: invalid src, dest buffer or length.", __func__);
+		return NULL;
+	}
+
+	if ((d > s && d <= s + slen - 1)
+		|| (d < s && s <= d + dmax - 1)) {
+		pr_err("%s: overlap happened.", __func__);
+		return NULL;
+	}
+
 	/*same memory block, no need to copy*/
 	if (d == s)
 		return d;
 
-	ASSERT((slen != 0) && (dmax != 0) && (dmax >= slen),
-		"invalid slen or dmax.");
-
-	ASSERT(((d > s) && (d > s + slen - 1))
-		|| ((d < s) && (s > d + dmax - 1)),
-		"overlap happened.");
-
 	dest8 = (uint8_t *)d;
 	src8 = (uint8_t *)s;
 
diff --git a/hypervisor/lib/strcpy.c b/hypervisor/lib/strcpy.c
index b14f6ef9e..fe569cf81 100644
--- a/hypervisor/lib/strcpy.c
+++ b/hypervisor/lib/strcpy.c
@@ -63,8 +63,10 @@ char *strcpy_s(char *d, size_t dmax, const char *s)
 	size_t dest_avail;
 	uint64_t overlap_guard;
 
-	ASSERT(s != NULL, "invalid input s.");
-	ASSERT((d != NULL) && (dmax != 0), "invalid input d or dmax.");
+	if (s == NULL || d == NULL || dmax == 0) {
+		pr_err("%s: invalid src, dest buffer or length.", __func__);
+		return NULL;
+	}
 
 	if (s == d)
 		return d;
@@ -75,7 +77,11 @@ char *strcpy_s(char *d, size_t dmax, const char *s)
 	dest_base = d;
 
 	while (dest_avail > 0) {
-		ASSERT(overlap_guard != 0, "overlap happened.");
+		if (overlap_guard == 0) {
+			pr_err("%s: overlap happened.", __func__);
+			*(--d) = '\0';
+			return NULL;
+		}
 
 		*d = *s;
 		if (*d == '\0')
@@ -87,7 +93,7 @@ char *strcpy_s(char *d, size_t dmax, const char *s)
 		overlap_guard--;
 	}
 
-	ASSERT(false, "dest buffer has no enough space.");
+	pr_err("%s: dest buffer has no enough space.", __func__);
 
 	/*
 	 * to avoid a string that is not
diff --git a/hypervisor/lib/strncpy.c b/hypervisor/lib/strncpy.c
index 30b69e326..38990e36c 100644
--- a/hypervisor/lib/strncpy.c
+++ b/hypervisor/lib/strncpy.c
@@ -66,8 +66,15 @@ char *strncpy_s(char *d, size_t dmax, const char *s, size_t slen)
 	size_t dest_avail;
 	uint64_t overlap_guard;
 
-	ASSERT((d != NULL) && (s != NULL), "invlaid input d or s");
-	ASSERT((dmax != 0) && (slen != 0), "invlaid input dmax or slen");
+	if (d == NULL || s == NULL) {
+		pr_err("%s: invlaid src or dest buffer", __func__);
+		return NULL;
+	}
+
+	if (dmax == 0 || slen == 0) {
+		pr_err("%s: invlaid length of src or dest buffer", __func__);
+		return NULL;
+	}
 
 	if (d == s)
 		return d;
@@ -78,7 +85,11 @@ char *strncpy_s(char *d, size_t dmax, const char *s, size_t slen)
 	dest_avail = dmax;
 
 	while (dest_avail > 0) {
-		ASSERT(overlap_guard != 0, "overlap happened.");
+		if (overlap_guard == 0) {
+			pr_err("%s: overlap happened.", __func__);
+			*(--d) = '\0';
+			return NULL;
+		}
 
 		if (slen == 0) {
 			*d = '\0';
@@ -96,7 +107,7 @@ char *strncpy_s(char *d, size_t dmax, const char *s, size_t slen)
 		overlap_guard--;
 	}
 
-	ASSERT(false, "dest buffer has no enough space.");
+	pr_err("%s: dest buffer has no enough space.", __func__);
 
 	/*
 	 * to avoid a string that is not