child_process: retain reference to data with advanced serialization

Do the same thing we do for other streams, and retain a reference to
the Buffer that was sent over IPC while the write request is active,
so that it doesn’t get garbage collected while the data is still in
flight.

(This is a good example of why it’s a bad idea that we’re not re-using
the general streams implementation for IPC and instead maintain
separate usage of the low-level I/O primitives.)

Fixes: https://github.com/nodejs/node/issues/34797

PR-URL: https://github.com/nodejs/node/pull/38728
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/lib/internal/child_process/serialization.js b/lib/internal/child_process/serialization.js
index f61a6b6f255..ec858f401be 100644
--- a/lib/internal/child_process/serialization.js
+++ b/lib/internal/child_process/serialization.js
@@ -12,6 +12,7 @@ const { StringDecoder } = require('string_decoder');
 const v8 = require('v8');
 const { isArrayBufferView } = require('internal/util/types');
 const assert = require('internal/assert');
+const { streamBaseState, kLastWriteWasAsync } = internalBinding('stream_wrap');
 
 const kMessageBuffer = Symbol('kMessageBuffer');
 const kJSONBuffer = Symbol('kJSONBuffer');
@@ -82,10 +83,16 @@ const advanced = {
     const serializedMessage = ser.releaseBuffer();
     const sizeBuffer = Buffer.allocUnsafe(4);
     sizeBuffer.writeUInt32BE(serializedMessage.length);
-    return channel.writeBuffer(req, Buffer.concat([
+
+    const buffer = Buffer.concat([
       sizeBuffer,
       serializedMessage,
-    ]), handle);
+    ]);
+    const result = channel.writeBuffer(req, buffer, handle);
+    // Mirror what stream_base_commons.js does for Buffer retention.
+    if (streamBaseState[kLastWriteWasAsync])
+      req.buffer = buffer;
+    return result;
   },
 };