static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
{
	ENTER();

	if (!opts || !*opts)
		return 0;

	for (;;) {
		unsigned long value;
		char *eq, *comma;

		/* Option limit */
		comma = strchr(opts, ',');
		if (comma)
			*comma = 0;

		/* Value limit */
		eq = strchr(opts, '=');
		if (unlikely(!eq)) {
			pr_err("'=' missing in %s\n", opts);
			return -EINVAL;
		}
		*eq = 0;

		/* Parse value */
		if (kstrtoul(eq + 1, 0, &value)) {
			pr_err("%s: invalid value: %s\n", opts, eq + 1);
			return -EINVAL;
		}

		/* Interpret option */
		switch (eq - opts) {
		case 13:
			if (!memcmp(opts, "no_disconnect", 13))
				data->no_disconnect = !!value;
			else
				goto invalid;
			break;
		case 5:
			if (!memcmp(opts, "rmode", 5))
				data->root_mode  = (value & 0555) | S_IFDIR;
			else if (!memcmp(opts, "fmode", 5))
				data->perms.mode = (value & 0666) | S_IFREG;
			else
				goto invalid;
			break;

		case 4:
			if (!memcmp(opts, "mode", 4)) {
				data->root_mode  = (value & 0555) | S_IFDIR;
				data->perms.mode = (value & 0666) | S_IFREG;
			} else {
				goto invalid;
			}
			break;

		case 3:
			if (!memcmp(opts, "uid", 3)) {
				data->perms.uid = make_kuid(current_user_ns(), value);
				if (!uid_valid(data->perms.uid)) {
					pr_err("%s: unmapped value: %lu\n", opts, value);
					return -EINVAL;
				}
			} else if (!memcmp(opts, "gid", 3)) {
				data->perms.gid = make_kgid(current_user_ns(), value);
				if (!gid_valid(data->perms.gid)) {
					pr_err("%s: unmapped value: %lu\n", opts, value);
					return -EINVAL;
				}
			} else {
				goto invalid;
			}
			break;

		default:
invalid:
			pr_err("%s: invalid option\n", opts);
			return -EINVAL;
		}

		/* Next iteration */
		if (!comma)
			break;
		opts = comma + 1;
	}

	return 0;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.