diff --git a/src/infra/restart.deferral-timeout.test.ts b/src/infra/restart.deferral-timeout.test.ts
index 5eacc475016..80f20306494 100644
--- a/src/infra/restart.deferral-timeout.test.ts
+++ b/src/infra/restart.deferral-timeout.test.ts
@@ -66,6 +66,23 @@ describe("deferGatewayRestartUntilIdle timeout", () => {
     expect(hooks.onTimeout).toHaveBeenCalledOnce();
   });
 
+  it("clamps oversized poll intervals instead of polling immediately", () => {
+    const hooks: RestartDeferralHooks = {
+      onReady: vi.fn(),
+    };
+    let pending = 1;
+
+    deferGatewayRestartUntilIdle({
+      getPendingCount: () => pending,
+      pollMs: Number.MAX_SAFE_INTEGER,
+      hooks,
+    });
+
+    pending = 0;
+    vi.advanceTimersByTime(1);
+    expect(hooks.onReady).not.toHaveBeenCalled();
+  });
+
   it("carries timeout restart intent when the deferral budget is exhausted", () => {
     const hooks: RestartDeferralHooks = {
       onTimeout: vi.fn(),
diff --git a/src/infra/restart.ts b/src/infra/restart.ts
index 9b2c50594f9..271bcf5766e 100644
--- a/src/infra/restart.ts
+++ b/src/infra/restart.ts
@@ -9,6 +9,7 @@ import {
   resolveGatewaySystemdServiceName,
 } from "../daemon/constants.js";
 import { createSubsystemLogger } from "../logging/subsystem.js";
+import { resolveTimerTimeoutMs } from "../shared/number-coercion.js";
 import { replaceFileAtomicSync } from "./replace-file.js";
 import { cleanStaleGatewayProcessesSync, findGatewayPidsOnPortSync } from "./restart-stale-pids.js";
 import type { RestartAttempt } from "./restart.types.js";
@@ -494,8 +495,7 @@ export function deferGatewayRestartUntilIdle(opts: {
   reason?: string;
   timeoutIntent?: GatewayRestartIntent;
 }): void {
-  const pollMsRaw = opts.pollMs ?? DEFAULT_DEFERRAL_POLL_MS;
-  const pollMs = Math.max(10, Math.floor(pollMsRaw));
+  const pollMs = resolveTimerTimeoutMs(opts.pollMs, DEFAULT_DEFERRAL_POLL_MS, 10);
   const maxWaitMs =
     typeof opts.maxWaitMs === "number" && Number.isFinite(opts.maxWaitMs) && opts.maxWaitMs > 0
       ? Math.max(pollMs, Math.floor(opts.maxWaitMs))