diff --git a/ChangeLog b/ChangeLog
index c0eacbcc79..b6a0e6ebf4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Tue May  7 12:15:24 2013  Tanaka Akira  <akr@fsij.org>
+
+	* ext/socket/ancdata.c (bsock_recvmsg_internal): Add a cast to
+	  suppress warning.
+	  Bionic defines socklen_t as int.
+	  Bionic defines msg_controllen as unsigned int (__kernel_size_t)
+	  instead of socklen_t as POSIX.
+
 Tue May  7 12:12:42 2013  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/ancdata.c (ancillary_inspect): Don't call
diff --git a/ext/socket/ancdata.c b/ext/socket/ancdata.c
index ac79e65689..eb36402720 100644
--- a/ext/socket/ancdata.c
+++ b/ext/socket/ancdata.c
@@ -1632,7 +1632,7 @@ bsock_recvmsg_internal(int argc, VALUE *argv, VALUE sock, int nonblock)
         if (NIL_P(vmaxctllen) && (mh.msg_flags & MSG_CTRUNC)) {
 #define BIG_ENOUGH_SPACE 65536
             if (BIG_ENOUGH_SPACE < maxctllen &&
-                mh.msg_controllen < (socklen_t)(maxctllen - BIG_ENOUGH_SPACE)) {
+                (socklen_t)mh.msg_controllen < (socklen_t)(maxctllen - BIG_ENOUGH_SPACE)) {
                 /* there are big space bug truncated.
                  * file descriptors limit? */
                 if (!gc_done) {