nixos/chrony: add enableMemoryLocking option

Fixes #222629.

nixos/modules/services/networking/ntp/chrony.nix

@@ -27,7 +27,10 @@ let
     ${cfg.extraConfig}
   '';
 
-  chronyFlags = [ "-n" "-m" "-u" "chrony" "-f" "${configFile}" ] ++ cfg.extraFlags;
+  chronyFlags =
+    [ "-n" "-u" "chrony" "-f" "${configFile}" ]
+    ++ optional cfg.enableMemoryLocking "-m"
+    ++ cfg.extraFlags;
 in
 {
   options = {
@@ -73,6 +76,15 @@ in
         '';
       };
 
+      enableMemoryLocking = mkOption {
+        type = types.bool;
+        default = config.environment.memoryAllocator.provider != "graphene-hardened";
+        defaultText = ''config.environment.memoryAllocator.provider != "graphene-hardened"'';
+        description = lib.mdDoc ''
+          Whether to add the `-m` flag to lock memory.
+        '';
+      };
+
       enableNTS = mkOption {
         type = types.bool;
         default = false;