mysqladmin crash on execution of below command:

  #> mysqladmin -u root -p
  ...
  Segmentation fault (core dumped)

This is probably caused by memory corruption based on working with temp_argv[-1].

RHBZ: #1207041
Upstream report: https://mariadb.atlassian.net/browse/MDEV-7883

---
 client/mysqladmin.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/client/mysqladmin.cc b/client/mysqladmin.cc
index ffdc73f..cb0c558 100644
--- a/client/mysqladmin.cc
+++ b/client/mysqladmin.cc
@@ -1361,7 +1361,8 @@ static char **mask_password(int argc, char ***argv)
      }
     argc--;
   }
-  temp_argv[argc]= my_strdup((*argv)[argc], MYF(MY_FAE));
+  if (argc >= 0)
+    temp_argv[argc]= my_strdup((*argv)[argc], MYF(MY_FAE));
   return(temp_argv);
 }
 
-- 
1.9.1