[jira] [Commented] (BOOKKEEPER-924) addEntry() is susceptible to spurious wakeups

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/BOOKKEEPER-924?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15542341#comment-15542341 ] 

ASF GitHub Bot commented on BOOKKEEPER-924:
-------------------------------------------

GitHub user eolivelli opened a pull request:

    https://github.com/apache/bookkeeper/pull/60

    BOOKKEEPER-924 addEntry() is susceptible to spurious wakeups

    Use Java8 CompletableFuture instead of SyncCounter

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/eolivelli/bookkeeper BOOKKEEPER-924

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/bookkeeper/pull/60.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #60
    
----

----


> addEntry() is susceptible to spurious wakeups
> ---------------------------------------------
>
>                 Key: BOOKKEEPER-924
>                 URL: https://issues.apache.org/jira/browse/BOOKKEEPER-924
>             Project: Bookkeeper
>          Issue Type: Bug
>    Affects Versions: 4.3.2
>            Reporter: Venkateswararao Jujjuri (JV)
>            Assignee: Matteo Merli
>            Priority: Critical
>             Fix For: 4.5.0
>
>
> LedgerHandle sync interface heavily depends on SyncCounter to convert async interfaces
> into sync interfaces.
> Usaylly
> SyncCounter.inc()
> asyncCall()
> SyncCOunter.block(0)
> The block code is.
>    synchronized void block(int limit) throws InterruptedException {
>         while (i > limit) {
>             int prev = i;
>             wait();
>             if (i == prev) {
>                 break;
>             }
>         }
>     }
> Since 'i' is going to be same as 'prev' on spurious wakeup, and wait() can return on spurious wakeups. 



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