diff --git a/include/simdjson/common_defs.h b/include/simdjson/common_defs.h
index a485e28b5..44fcef7b0 100644
--- a/include/simdjson/common_defs.h
+++ b/include/simdjson/common_defs.h
@@ -31,8 +31,6 @@
 #define ISALIGNED_N(ptr, n) (((uintptr_t)(ptr) & ((n)-1)) == 0)
 
 #ifdef _MSC_VER
-// Visual Studio won't allow it:
-//#define ALLOW_SAME_PAGE_BUFFER_OVERRUN
 #define really_inline inline
 #define never_inline __declspec(noinline)
 
@@ -48,10 +46,11 @@
 
 #else
 
-// for non-Visual Studio compilers, we assume that same-page buffer overrun is fine:
-#ifndef ALLOW_SAME_PAGE_BUFFER_OVERRUN
-#define ALLOW_SAME_PAGE_BUFFER_OVERRUN
-#endif 
+// For non-Visual Studio compilers, we may assume that same-page buffer overrun is fine.
+// However, it will make it difficult to be "valgrind clean".
+//#ifndef ALLOW_SAME_PAGE_BUFFER_OVERRUN
+//#define ALLOW_SAME_PAGE_BUFFER_OVERRUN
+//#endif 
 
 // The following is likely unnecessarily complex.
 #ifdef __SANITIZE_ADDRESS__
diff --git a/src/parsedjson.cpp b/src/parsedjson.cpp
index b18b5b7d1..c5707c7d2 100644
--- a/src/parsedjson.cpp
+++ b/src/parsedjson.cpp
@@ -74,7 +74,13 @@ bool ParsedJson::allocateCapacity(size_t len, size_t maxdepth) {
 
       return false;
     }
-
+    /*
+    // We do not need to initialize this content for parsing, though we could
+    // need to initialize it for safety.
+    memset(string_buf, 0 , localstringcapacity); 
+    memset(structural_indexes, 0, max_structures * sizeof(uint32_t)); 
+    memset(tape, 0, localtapecapacity * sizeof(uint64_t)); 
+    */
     bytecapacity = len;
     depthcapacity = maxdepth;
     tapecapacity = localtapecapacity;
diff --git a/src/stage2_build_tape.cpp b/src/stage2_build_tape.cpp
index f3bf15b66..3b3b1a458 100644
--- a/src/stage2_build_tape.cpp
+++ b/src/stage2_build_tape.cpp
@@ -72,6 +72,9 @@ really_inline bool is_valid_null_atom(const uint8_t *loc) {
  ***********/
 WARN_UNUSED  ALLOW_SAME_PAGE_BUFFER_OVERRUN_QUALIFIER LENIENT_MEM_SANITIZER
 int unified_machine(const uint8_t *buf, size_t len, ParsedJson &pj) {
+#ifndef ALLOW_SAME_PAGE_BUFFER_OVERRUN
+  memset((uint8_t*)buf + len, 0, SIMDJSON_PADDING); // to please valgrind
+#endif
   uint32_t i = 0; // index of the structural character (0,1,2,3...)
   uint32_t idx;   // location of the structural character in the input (buf)
   uint8_t c; // used to track the (structural) character we are looking at, updated