--- zzzz-none-000/linux-3.10.107/security/keys/sysctl.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/security/keys/sysctl.c	2021-02-04 17:41:59.000000000 +0000
@@ -15,7 +15,7 @@
 
 static const int zero, one = 1, max = INT_MAX;
 
-ctl_table key_sysctls[] = {
+struct ctl_table key_sysctls[] = {
 	{
 		.procname = "maxkeys",
 		.data = &key_quota_maxkeys,
@@ -61,5 +61,16 @@
 		.extra1 = (void *) &zero,
 		.extra2 = (void *) &max,
 	},
+#ifdef CONFIG_PERSISTENT_KEYRINGS
+	{
+		.procname = "persistent_keyring_expiry",
+		.data = &persistent_keyring_expiry,
+		.maxlen = sizeof(unsigned),
+		.mode = 0644,
+		.proc_handler = proc_dointvec_minmax,
+		.extra1 = (void *) &zero,
+		.extra2 = (void *) &max,
+	},
+#endif
 	{ }
 };