diff --git a/drivers/platform/x86/lenovo/think-lmi.c b/drivers/platform/x86/lenovo/think-lmi.c
index e3e683bf3469..ca266657e16c 100644
--- a/drivers/platform/x86/lenovo/think-lmi.c
+++ b/drivers/platform/x86/lenovo/think-lmi.c
@@ -745,6 +745,8 @@ static ssize_t certificate_thumbprint_show(struct kobject *kobj, struct kobj_att
 		return -EOPNOTSUPP;
 
 	for (i = 0; i < ARRAY_SIZE(thumbtypes); i++) {
+		ssize_t ret;
+
 		if (tlmi_priv.pwdcfg.core.password_mode >= TLMI_PWDCFG_MODE_MULTICERT) {
 			/* Format: 'SVC | SMC, Thumbtype' */
 			wmistr = kasprintf(GFP_KERNEL, "%s,%s",
@@ -756,8 +758,12 @@ static ssize_t certificate_thumbprint_show(struct kobject *kobj, struct kobj_att
 		}
 		if (!wmistr)
 			return -ENOMEM;
-		count += cert_thumbprint(buf, wmistr, count);
+
+		ret = cert_thumbprint(buf, wmistr, count);
 		kfree(wmistr);
+		if (ret < 0)
+			return ret;
+		count = ret;
 	}
 
 	return count;