diff --git a/ChangeLog b/ChangeLog
index c7e834e7bc..df2aae8c20 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+Tue Feb 25 22:52:02 2014  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
+
+	* ext/dl/dl.c (rb_dl_realloc): use NUM2SIZET instead of NUM2INT.
+
+	* ext/fiddle/fiddle.c (rb_fiddle_realloc): ditto.
+
+Tue Feb 25 22:49:30 2014  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
+
+	* ext/dl/dl.c (rb_dl_malloc): use NUM2SIZET instead of NUM2INT.
+	  Coverity Scan found this bug.
+
+	* ext/fiddle/fiddle.c (rb_fiddle_malloc): ditto.
+
 Tue Feb 25 12:06:13 2014  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* win32/Makefile.sub: define PACKED_STRUCT.
diff --git a/ext/dl/dl.c b/ext/dl/dl.c
index 23f5d7fe6e..7ad77dd6b2 100644
--- a/ext/dl/dl.c
+++ b/ext/dl/dl.c
@@ -81,7 +81,7 @@ rb_dl_malloc(VALUE self, VALUE size)
 {
     void *ptr;
 
-    ptr = (void*)ruby_xmalloc(NUM2INT(size));
+    ptr = (void*)ruby_xmalloc(NUM2SIZET(size));
     return PTR2NUM(ptr);
 }
 
@@ -97,7 +97,7 @@ rb_dl_realloc(VALUE self, VALUE addr, VALUE size)
 {
     void *ptr = NUM2PTR(addr);
 
-    ptr = (void*)ruby_xrealloc(ptr, NUM2INT(size));
+    ptr = (void*)ruby_xrealloc(ptr, NUM2SIZET(size));
     return PTR2NUM(ptr);
 }
 
diff --git a/ext/fiddle/fiddle.c b/ext/fiddle/fiddle.c
index 7a7c708245..9f3d1537d6 100644
--- a/ext/fiddle/fiddle.c
+++ b/ext/fiddle/fiddle.c
@@ -48,7 +48,7 @@ rb_fiddle_malloc(VALUE self, VALUE size)
 {
     void *ptr;
 
-    ptr = (void*)ruby_xmalloc(NUM2INT(size));
+    ptr = (void*)ruby_xmalloc(NUM2SIZET(size));
     return PTR2NUM(ptr);
 }
 
@@ -64,7 +64,7 @@ rb_fiddle_realloc(VALUE self, VALUE addr, VALUE size)
 {
     void *ptr = NUM2PTR(addr);
 
-    ptr = (void*)ruby_xrealloc(ptr, NUM2INT(size));
+    ptr = (void*)ruby_xrealloc(ptr, NUM2SIZET(size));
     return PTR2NUM(ptr);
 }