From 75a919254992823c338b381407d9504850304b1d Mon Sep 17 00:00:00 2001
From: Mathias Buus <mathiasbuus@gmail.com>
Date: Thu, 30 Aug 2018 03:23:41 +0200
Subject: [PATCH] src: fix external memory usage going negative
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PR-URL: https://github.com/nodejs/node/pull/22594
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
---
 src/node_crypto.h                            |  4 ++-
 test/parallel/test-gc-tls-external-memory.js | 35 ++++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-gc-tls-external-memory.js

diff --git a/src/node_crypto.h b/src/node_crypto.h
index 269bccbc03a1d7..692978412fc023 100644
--- a/src/node_crypto.h
+++ b/src/node_crypto.h
@@ -198,7 +198,9 @@ class SecureContext : public BaseObject {
   }
 
   inline void Reset() {
-    env()->isolate()->AdjustAmountOfExternalAllocatedMemory(-kExternalSize);
+    if (ctx_ != nullptr) {
+      env()->isolate()->AdjustAmountOfExternalAllocatedMemory(-kExternalSize);
+    }
     ctx_.reset();
     cert_.reset();
     issuer_.reset();
diff --git a/test/parallel/test-gc-tls-external-memory.js b/test/parallel/test-gc-tls-external-memory.js
new file mode 100644
index 00000000000000..c19fbbe5088306
--- /dev/null
+++ b/test/parallel/test-gc-tls-external-memory.js
@@ -0,0 +1,35 @@
+'use strict';
+// Flags: --expose-gc
+
+// Tests that memoryUsage().external doesn't go negative
+// when a lot tls connections are opened and closed
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+
+const assert = require('assert');
+const net = require('net');
+const tls = require('tls');
+
+// Payload doesn't matter. We just need to have the tls
+// connection try and connect somewhere.
+const yolo = Buffer.alloc(10000).fill('yolo');
+const server = net.createServer(function(socket) {
+  socket.write(yolo);
+});
+
+server.listen(0, common.mustCall(function() {
+  const { port } = server.address();
+  let runs = 0;
+  connect();
+
+  function connect() {
+    global.gc();
+    assert(process.memoryUsage().external >= 0);
+    if (runs++ < 512)
+      tls.connect(port).on('error', connect);
+    else
+      server.close();
+  }
+}));