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Posted to dev@helix.apache.org by neutronsharc <gi...@git.apache.org> on 2016/05/19 22:43:15 UTC

[GitHub] helix pull request: fixed a bug at WriteLock caused by read-delete...

GitHub user neutronsharc opened a pull request:

    https://github.com/apache/helix/pull/44

    fixed a bug at WriteLock caused by read-delete race on a znode.

    Bug description:
    T1 currently owns a zk lock as signified by znode n1, T2 creates a znode n2
    and realizes n1 is saller. T2 is going to register a watcher on n1 but at the
    same moment T1 released n1. T2 register fails, breaks from while loop, and wait().
    Nobody will ever wake up T2 again. Consequently all subsequent callers for the
    same lock are also blocked.
    
    Test:
    Repeated our loadtest and the bug doesn't reappear.
    
    For detailed bug report see this post:
    http://mail-archives.apache.org/mod_mbox/helix-dev/201605.mbox/%3CCAB-bdySG8Uf6c1fyVHpSu-5pD99VHE=mrL=j3QNkaTWaEtKQ+w@mail.gmail.com%3E

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

    $ git pull https://github.com/neutronsharc/helix 0.7.1-bugfix

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

    https://github.com/apache/helix/pull/44.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 #44
    
----
commit 6ecac13e42c52f854450c98e33d2e2624d0f6167
Author: neutronsharc <ne...@gmail.com>
Date:   2016-05-19T22:29:56Z

    fixed a bug at WriteLock caused by read-delete race on a znode.
    
    Bug description:
    T1 currently owns a zk lock as signified by znode n1, T2 creates a znode n2
    and realizes n1 is saller. T2 is going to register a watcher on n1 but at the
    same moment T1 released n1. T2 register fails, breaks from while loop, and wait().
    Nobody will ever wake up T2 again. Consequently all subsequent callers for the
    same lock are also blocked.
    
    Test:
    Repeated our loadtest and the bug doesn't reappear.
    
    For detailed bug report see this post:
    http://mail-archives.apache.org/mod_mbox/helix-dev/201605.mbox/%3CCAB-bdySG8Uf6c1fyVHpSu-5pD99VHE=mrL=j3QNkaTWaEtKQ+w@mail.gmail.com%3E

----


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[GitHub] helix pull request: fixed a bug at WriteLock caused by read-delete...

Posted by asfgit <gi...@git.apache.org>.
Github user asfgit closed the pull request at:

    https://github.com/apache/helix/pull/44


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[GitHub] helix pull request: fixed a bug at WriteLock caused by read-delete...

Posted by kishoreg <gi...@git.apache.org>.
Github user kishoreg commented on the pull request:

    https://github.com/apache/helix/pull/44#issuecomment-221774907
  
    LGTM


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