diff --git a/migration/xbzrle.c b/migration/xbzrle.c
index 21b92d4eae..c6f8b20917 100644
--- a/migration/xbzrle.c
+++ b/migration/xbzrle.c
@@ -197,10 +197,6 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
     __m512i r = _mm512_set1_epi32(0);
 
     while (count512s) {
-        if (d + 2 > dlen) {
-            return -1;
-        }
-
         int bytes_to_check = 64;
         uint64_t mask = 0xffffffffffffffff;
         if (count512s == 1) {
@@ -216,6 +212,9 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
 
         bool is_same = (comp & 0x1);
         while (bytes_to_check) {
+            if (d + 2 > dlen) {
+                return -1;
+            }
             if (is_same) {
                 if (nzrun_len) {
                     d += uleb128_encode_small(dst + d, nzrun_len);