diff --git a/init/main.c b/init/main.c
index f4e6001ebe79..91e74827f858 100644
--- a/init/main.c
+++ b/init/main.c
@@ -327,7 +327,7 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
 {
 	struct xbc_node *knode, *vnode;
 	char *end = buf + size;
-	const char *val;
+	const char *val, *q;
 	int ret;
 
 	xbc_node_for_each_key_value(root, knode, val) {
@@ -345,8 +345,9 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
 			continue;
 		}
 		xbc_array_for_each_value(vnode, val) {
-			ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
-				       xbc_namebuf, val);
+			q = strpbrk(val, " \t\r\n") ? "\"" : "";
+			ret = snprintf(buf, rest(buf, end), "%s=%s%s%s ",
+				       xbc_namebuf, q, val, q);
 			if (ret < 0)
 				return ret;
 			buf += ret;
@@ -627,14 +628,16 @@ static void __init setup_command_line(char *command_line)
 
 	if (extra_command_line)
 		xlen = strlen(extra_command_line);
-	if (extra_init_args)
+	if (extra_init_args) {
+		extra_init_args = strim(extra_init_args); /* remove trailing space */
 		ilen = strlen(extra_init_args) + 4; /* for " -- " */
+	}
 
-	len = xlen + strlen(boot_command_line) + 1;
+	len = xlen + strlen(boot_command_line) + ilen + 1;
 
-	saved_command_line = memblock_alloc(len + ilen, SMP_CACHE_BYTES);
+	saved_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 	if (!saved_command_line)
-		panic("%s: Failed to allocate %zu bytes\n", __func__, len + ilen);
+		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 
 	len = xlen + strlen(command_line) + 1;