Tomcat experiences high CPU in OpenSSLEngine.unwrap

Issue

• We see high CPU in threads that appear to be in an infinite loop in org.apache.tomcat.util.net.openssl.OpenSSLEngine.unwrap:

Thread 2844: (state = IN_JAVA)
 - java.nio.Bits.tryReserveMemory(long, int) @bci=29, line=712 (Compiled frame; information may be imprecise)
 - java.nio.Bits.reserveMemory(long, int) @bci=24, line=652 (Compiled frame)
 - java.nio.DirectByteBuffer.<init>(int) @bci=38, line=123 (Compiled frame)
 - java.nio.ByteBuffer.allocateDirect(int) @bci=5, line=311 (Compiled frame)
 - org.apache.tomcat.util.net.openssl.OpenSSLEngine.readPlaintextData(long, java.nio.ByteBuffer) @bci=84, line=331 (Compiled frame)
 - org.apache.tomcat.util.net.openssl.OpenSSLEngine.unwrap(java.nio.ByteBuffer, java.nio.ByteBuffer[], int, int) @bci=418, line=584 (Compiled frame)
 - javax.net.ssl.SSLEngine.unwrap(java.nio.ByteBuffer, java.nio.ByteBuffer) @bci=12, line=626 (Compiled frame)
 - org.apache.tomcat.util.net.SecureNioChannel.read(java.nio.ByteBuffer) @bci=77, line=617 (Compiled frame)
 - org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper.fillReadBuffer(boolean, java.nio.ByteBuffer) @bci=105, line=1229 (Compiled frame)
 - org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper.read(boolean, java.nio.ByteBuffer) @bci=48, line=1141 (Compiled frame)
 - org.apache.coyote.http11.Http11InputBuffer.fill(boolean) @bci=147, line=780 (Compiled frame)
 - org.apache.coyote.http11.Http11InputBuffer.parseRequestLine(boolean, int, int) @bci=49, line=356 (Compiled frame)
 - org.apache.coyote.http11.Http11Processor.service(org.apache.tomcat.util.net.SocketWrapperBase) @bci=108, line=260 (Compiled frame)
 - org.apache.coyote.AbstractProcessorLight.process(org.apache.tomcat.util.net.SocketWrapperBase, org.apache.tomcat.util.net.SocketEvent) @bci=170, line=65 (Compiled frame)
 - org.apache.coyote.AbstractProtocol$ConnectionHandler.process(org.apache.tomcat.util.net.SocketWrapperBase, org.apache.tomcat.util.net.SocketEvent) @bci=505, line=868 (Compiled frame)
 - org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun() @bci=214, line=1590 (Compiled frame)
 - org.apache.tomcat.util.net.SocketProcessorBase.run() @bci=21, line=49 (Compiled frame)
 - java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) @bci=95, line=1149 (Compiled frame)
 - java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=5, line=624 (Interpreted frame)
 - org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run() @bci=4, line=61 (Interpreted frame)
 - java.lang.Thread.run() @bci=11, line=748 (Interpreted frame)