High CPU in InternalInputBuffer.nextRequest after updating to 6.4.13

Issue

• We recently updated to 6.4.13. Afterwards, we often see high CPU in threads executing the following:

"http-0.0.0.0:8080-21" #173 daemon prio=5 os_prio=0 tid=0x00007f0160056000 nid=0xd06 runnable [0x00007f017d350000]
java.lang.Thread.State: RUNNABLE
    at org.apache.coyote.http11.InternalInputBuffer.nextRequest(InternalInputBuffer.java:290)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:893)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:656)
- locked <0x00000007b47221c8> (a org.apache.coyote.http11.Http11Processor)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:926)
    at java.lang.Thread.run(Thread.java:745)

• Randomly despite almost daily jvm restarts we detect saturation of the CPU