diff --git a/src/core/impl/utils/persistent_cache.cpp b/src/core/impl/utils/persistent_cache.cpp
index 75996a24..ec6651e8 100644
--- a/src/core/impl/utils/persistent_cache.cpp
+++ b/src/core/impl/utils/persistent_cache.cpp
@@ -176,11 +176,9 @@ AlgoChooserProfileCache::get(const Key &key) {
 
         auto entry_len = read_uint32();
         mgb_assert(buf + entry_len <= buf_end);
-        int rep;
         auto nr = sscanf(reinterpret_cast<const char*>(buf), ENTRY_FMT,
-                &rep, &i.time, &i.workspace);
+                         &i.reproducible, &i.time, &i.workspace);
         mgb_assert(nr == 3);
-        i.reproducible = rep;
         buf += entry_len;
     }
     mgb_assert(buf == buf_end);
@@ -228,6 +226,8 @@ void AlgoChooserProfileCache::put(const Key &key, Result &result) {
         val.resize(pos + SPR_SIZE);
         uint32_t nr = snprintf(&val[pos], SPR_SIZE,
                 ENTRY_FMT, i.reproducible, i.time, i.workspace);
+        //! for memory boundary failed, snprintf ret do not contain \0
+        nr += 1;
         mgb_assert(nr < SPR_SIZE);
         memcpy(&val[pos - sizeof(uint32_t)], &nr, sizeof(nr));
         val.resize(pos + nr);
diff --git a/src/core/include/megbrain/utils/persistent_cache.h b/src/core/include/megbrain/utils/persistent_cache.h
index bd6ce5a2..5ad1f80b 100644
--- a/src/core/include/megbrain/utils/persistent_cache.h
+++ b/src/core/include/megbrain/utils/persistent_cache.h
@@ -100,7 +100,8 @@ namespace mgb {
 
             struct ResultEntry {
                 std::string algo;   //! identifier of the algorithm
-                bool reproducible;  //! whether algorithm is reproducible
+                //! sscanf will up bool as int
+                int reproducible;  //! whether algorithm is reproducible
                 double time;        //! execution time in seconds
                 size_t workspace;   //! workspace in bytes
             };