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HTTP/2: Prevent memory leak when trying to create new streams on a connection that received a GOAWAY. (#9674)

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Motivation:

In https://github.com/netty/netty/issues/8692, `Http2FrameCodec` was
updated to keep track of all "being initialized" streams, allocating
memory before initialization begins, and releasing memory after
initialization completes successfully.

In some instances where stream initialization fails (e.g. because this
connection has received a GOAWAY frame), this memory is never released.

Modifications:

This change updates the `Http2FrameCodec` to use a separate promise
for monitoring the success of sending HTTP2 headers. When sending of
headers fails, we now make sure to release memory allocated for stream
initialization.

Result:

After this change, failures in writing HTTP2 Headers (e.g. because this
connection has received a GOAWAY frame) will no longer leak memory.
This commit is contained in:
Matthew Miller 2019-10-16 19:32:45 -07:00 committed by Norman Maurer
parent 3d7dba373f
commit bbc34d0eda
2 changed files with 51 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
codec-http2/src/main/java/io/netty/handler/codec/http2/Http2FrameCodec.java
View File

@ -207,6 +207,15 @@ public class Http2FrameCodec extends Http2ConnectionHandler {
}
}
/**
* Retrieve the number of streams currently in the process of being initialized.
*
* This is package-private for testing only.
*/
int numInitializingStreams() {
return frameStreamToInitializeMap.size();
}
@Override
public final void handlerAdded(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
@ -411,8 +420,19 @@ public class Http2FrameCodec extends Http2ConnectionHandler {
// We should not re-use ids.
assert old == null;
// Clean up the stream being initialized if writing the headers fails.
promise.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture channelFuture) {
if (!channelFuture.isSuccess()) {
frameStreamToInitializeMap.remove(streamId);
}
}
});
encoder().writeHeaders(ctx, streamId, headersFrame.headers(), headersFrame.padding(),
headersFrame.isEndStream(), promise);
if (!promise.isDone()) {
numBufferedStreams++;
promise.addListener(bufferedStreamsListener);
@ -431,7 +451,6 @@ public class Http2FrameCodec extends Http2ConnectionHandler {
}
private final class ConnectionListener extends Http2ConnectionAdapter {
@Override
public void onStreamAdded(Http2Stream stream) {
DefaultHttp2FrameStream frameStream = frameStreamToInitializeMap.remove(stream.id());

27
codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameCodecTest.java
View File

@ -665,6 +665,33 @@ public class Http2FrameCodecTest {
assertFalse(channel.finishAndReleaseAll());
}
@Test
public void doNotLeakOnFailedInitializationForChannels() throws Exception {
setUp(Http2FrameCodecBuilder.forServer(), new Http2Settings().maxConcurrentStreams(2));
Http2FrameStream stream1 = frameCodec.newStream();
Http2FrameStream stream2 = frameCodec.newStream();
ChannelPromise stream1HeaderPromise = channel.newPromise();
ChannelPromise stream2HeaderPromise = channel.newPromise();
channel.writeAndFlush(new DefaultHttp2HeadersFrame(new DefaultHttp2Headers()).stream(stream1),
stream1HeaderPromise);
channel.runPendingTasks();
frameInboundWriter.writeInboundGoAway(stream1.id(), 0L, Unpooled.EMPTY_BUFFER);
channel.writeAndFlush(new DefaultHttp2HeadersFrame(new DefaultHttp2Headers()).stream(stream2),
stream2HeaderPromise);
channel.runPendingTasks();
assertTrue(stream1HeaderPromise.syncUninterruptibly().isSuccess());
assertTrue(stream2HeaderPromise.isDone());
assertEquals(0, frameCodec.numInitializingStreams());
assertFalse(channel.finishAndReleaseAll());
}
@Test
public void streamIdentifiersExhausted() throws Http2Exception {
int maxServerStreamId = Integer.MAX_VALUE - 1;