diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 388cc1ff61..43175ffcde 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2016-10-24  Luis Machado  <lgustavo@codesourcery.com>
+
+	* exec.c (exec_file_locate_attach): Prevent NULL pointer dereference
+	when duplicating a string.
+
 2016-10-24  Luis Machado  <lgustavo@codesourcery.com>
 
 	* exec.c (exception_print_same): Fix string comparison to use
diff --git a/gdb/exec.c b/gdb/exec.c
index 67ecc63630..6e2a296d2e 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -227,7 +227,8 @@ exec_file_locate_attach (int pid, int defer_bp_reset, int from_tty)
       prev_err = err;
 
       /* Save message so it doesn't get trashed by the catch below.  */
-      prev_err.message = xstrdup (err.message);
+      if (err.message != NULL)
+	prev_err.message = xstrdup (err.message);
     }
   END_CATCH