diff --git a/lustre/llite/llite_lib.c b/lustre/llite/llite_lib.c
index fcc78fc0b3c118a68382fc2fb4677561147aaff1..b59fdb6b35b7059a623cfae09ac18247af00dbd2 100644
--- a/lustre/llite/llite_lib.c
+++ b/lustre/llite/llite_lib.c
@@ -391,6 +391,8 @@ static int client_common_fill_super(struct super_block *sb,
 
         sb->s_op = &lustre_super_operations;
 #if THREAD_SIZE >= 8192
+        /* Disable the NFS export because of stack overflow
+         * when THREAD_SIZE < 8192. Please refer to 17630. */
         sb->s_export_op = &lustre_export_operations;
 #endif