bootconfig: init: Fix memblock leak in xbc_make_cmdline()

commit 1ae43851b18afe861120ebd7c426dc44f06bb2bd upstream.

Free unused memblock in a error case to fix memblock leak
in xbc_make_cmdline().

Link: https://lkml.kernel.org/r/163177339181.682366.8713781325929549256.stgit@devnote2

Fixes: 51887d03aca1 ("bootconfig: init: Allow admin to use bootconfig for kernel command line")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/init/main.c b/init/main.c
index dd26a42..4fe58ed 100644
--- a/init/main.c
+++ b/init/main.c
@@ -380,6 +380,7 @@ static char * __init xbc_make_cmdline(const char *key)
 	ret = xbc_snprint_cmdline(new_cmdline, len + 1, root);
 	if (ret < 0 || ret > len) {
 		pr_err("Failed to print extra kernel cmdline.\n");
+		memblock_free(__pa(new_cmdline), len + 1);
 		return NULL;
 	}