I was unable to reproduce these so far, happened twice in recent test runs:
gradle :core:integTest -Dtests.seed=1FFB9F0D780D57E7 -Dtests.class=org.elasticsearch.search.basic.SearchWithRandomIOExceptionsIT -Dtests.method="testRandomDirectoryIOExceptions" -Dtests.security.manager=true -Dtests.jvm.argline="-XX:-UseConcMarkSweepGC -XX:+UseG1GC" -Dtests.locale=fr-CA -Dtests.timezone=Asia/Baku
Most of the exceptions in the log are expected, hard to spot the real cause, one of the two failures looks as if a thread is lingering around, the other one shows an uncaught exception for a set of lucene files.
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+g1gc/1062/console
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+master+periodic/1489/console