diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b706e712f8a..50fc8deb409 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2016-08-19  Yao Qi  <yao.qi@linaro.org>
+
+	* completer.c (linespec_location_completer): Make file_to_match
+	null-terminated.
+
 2016-08-19  Pedro Alves  <palves@redhat.com>
 
 	* amd64-tdep.c (amd64_relocate_instruction) <callq>: Handle return
diff --git a/gdb/completer.c b/gdb/completer.c
index 5c3b3fcfaae..d0e6bc80fd1 100644
--- a/gdb/completer.c
+++ b/gdb/completer.c
@@ -264,7 +264,8 @@ linespec_location_completer (struct cmd_list_element *ignore,
       char *s;
 
       file_to_match = (char *) xmalloc (colon - text + 1);
-      strncpy (file_to_match, text, colon - text + 1);
+      strncpy (file_to_match, text, colon - text);
+      file_to_match[colon - text] = '\0';
       /* Remove trailing colons and quotes from the file name.  */
       for (s = file_to_match + (colon - text);
 	   s > file_to_match;