[infinispan-issues] [JBoss JIRA] (ISPN-5522) LIRS BoundedConcurrentHashMapv8 eviction for tree bin missing check

[William Burns (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-5522?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13074360#comment-13074360 ] 

William Burns commented on ISPN-5522:
-------------------------------------

It is quite difficult to produce a test case for this.  But it seems that essentially an entry in a TreeBin (that is a segment that had at least 8 elements in it) had an element that was at both the head of the LIRS hot stack and LIRS cold queue.  It was being removed from both at the same time.

The first thread removed it from the LIRS hot stack making it to HIR_NONRESIDENT and setting the value to the NULL object and raising the notification
The second thread then removed from the cold queue and found it should transition to EVICTING since it was no longer in a queue.  This then tried to raise the event since it didn't have the proper null check.

> LIRS BoundedConcurrentHashMapv8 eviction for tree bin missing check
> -------------------------------------------------------------------
>
>                 Key: ISPN-5522
>                 URL: https://issues.jboss.org/browse/ISPN-5522
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Eviction
>    Affects Versions: 7.2.2.Final
>            Reporter: William Burns
>            Assignee: William Burns
>             Fix For: 8.0.0.Alpha2, 7.2.3.Final
>
>
> This was discovered at https://developer.jboss.org/message/932819?et=watches.email.thread
> The else if branch when a TreeBin is in place is missing a check to make sure eviction removal is only done if the value is non null.
> This line needs a {code} if (pv != null) {code} check around this [line|https://github.com/infinispan/infinispan/blob/40c2050c233c6fbfc382bd4208dbfdf1a6a9a0a4/commons/src/main/java/org/infinispan/commons/util/concurrent/jdk8backported/BoundedEquivalentConcurrentHashMapV8.java#L2619]



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