bootconfig: Fix to find the initargs correctly

Since the parse_args() stops parsing at '--', bootconfig_params()
will never get the '--' as param and initargs_found never be true.
In the result, if we pass some init arguments via the bootconfig,
those are always appended to the kernel command line with '--'
even if the kernel command line already has '--'.

To fix this correctly, check the return value of parse_args()
and set initargs_found true if the return value is not an error
but a valid address.

Link: https://lkml.kernel.org/r/159650953285.270383.14822353843556363851.stgit@devnote2

Fixes: f61872bb ("bootconfig: Use parse_args() to find bootconfig and '--'")
Cc: stable@vger.kernel.org
Reported-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

init/main.c

@@ -387,8 +387,6 @@ static int __init bootconfig_params(char *param, char *val,
 {
 	if (strcmp(param, "bootconfig") == 0) {
 		bootconfig_found = true;
-	} else if (strcmp(param, "--") == 0) {
-		initargs_found = true;
 	}
 	return 0;
 }
@@ -399,19 +397,23 @@ static void __init setup_boot_config(const char *cmdline)
 	const char *msg;
 	int pos;
 	u32 size, csum;
-	char *data, *copy;
+	char *data, *copy, *err;
 	int ret;
 
 	/* Cut out the bootconfig data even if we have no bootconfig option */
 	data = get_boot_config_from_initrd(&size, &csum);
 
 	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
-	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
+	err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
 			 bootconfig_params);
 
-	if (!bootconfig_found)
+	if (IS_ERR(err) || !bootconfig_found)
 		return;
 
+	/* parse_args() stops at '--' and returns an address */
+	if (err)
+		initargs_found = true;
+
 	if (!data) {
 		pr_err("'bootconfig' found on command line, but no bootconfig found\n");
 		return;