Details
Minor Description
Zookeeper refresh thread for Kerberos have the same problem in the reLogin() https://github.com/apache/zookeeper/blob/release-3.5.5/zookeeper-server/src/main/java/org/apache/zookeeper/Login.java#L413 function as describe in https://issues.apache.org/jira/browse/KAFKA-12730
The refresh thread for Kerberos performs re-login by logging out and then logging in again. If login fails, we retry after a backoff. Every iteration of the loop performs loginContext.logout() and loginContext.login(). If login fails, we end up with two consecutive logouts. This used to work, but from Java 9 onwards, this results in a NullPointerException due to https://bugs.openjdk.java.net/browse/JDK-8173069. We should check if logout is required before attempting logout.
A NPE is throw if multiple logout() is invoke multiple times:
2022-02-14 18:38:11,899 ERROR org.apache.zookeeper.Login: Failed to refresh TGT: refresh thread exiting now. javax.security.auth.login.LoginException: java.lang.NullPointerException: invalid null input(s) at java.base/java.util.Objects.requireNonNull(Objects.java:246) at java.base/javax.security.auth.Subject$SecureSet.remove(Subject.java:1172) at java.base/java.util.Collections$SynchronizedCollection.remove(Collections.java:2043) at jdk.security.auth/com.sun.security.auth.module.Krb5LoginModule.logout(Krb5LoginModule.java:1202) at java.base/javax.security.auth.login.LoginContext.invoke(LoginContext.java:732) at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:665) at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:663) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/javax.security.auth.login.LoginContext.invokePriv(LoginContext.java:663) at java.base/javax.security.auth.login.LoginContext.logout(LoginContext.java:613) at org.apache.zookeeper.Login.reLogin(Login.java:413) at org.apache.zookeeper.Login.access$500(Login.java:49) at org.apache.zookeeper.Login$1.run(Login.java:240) at java.base/java.lang.Thread.run(Thread.java:834) at java.base/javax.security.auth.login.LoginContext.invoke(LoginContext.java:821) at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:665) at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:663) at java.base/java.security.AccessController.doPrivileged(Native Method) at java.base/javax.security.auth.login.LoginContext.invokePriv(LoginContext.java:663) at java.base/javax.security.auth.login.LoginContext.logout(LoginContext.java:613) at org.apache.zookeeper.Login.reLogin(Login.java:413) at org.apache.zookeeper.Login.access$500(Login.java:49) at org.apache.zookeeper.Login$1.run(Login.java:240) at java.base/java.lang.Thread.run(Thread.java:834)
