[jira] [Created] (ZOOKEEPER-2320) C-client crashes when removing watcher asynchronously in "local" mode

["Hadriel Kaplan (JIRA)" <ji...@apache.org>]

Hadriel Kaplan created ZOOKEEPER-2320:
-----------------------------------------

             Summary: C-client crashes when removing watcher asynchronously in "local" mode
                 Key: ZOOKEEPER-2320
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2320
             Project: ZooKeeper
          Issue Type: Bug
          Components: c client
    Affects Versions: 3.5.1
            Reporter: Hadriel Kaplan


The C-client library will crash when invoking the asynchronous {{zoo_aremove_watchers()}} API function with the '{{local}}' argument set to 1.

The reason is: if the local argument is 1/true, then the code does '{{notify_sync_completion((struct sync_completion *)data);}}' But casting the '{{data}}' variable to a {{sync_completion}} struct pointer is bogus/invalid, and when it's later handles as that struct pointer it's accessing invalid memory.

As a side note: it will work ok when called _synchronously_ through {{zoo_remove_watchers()}}, because that function creates a {{sync_completion}} struct and passes it to the asynch {{zoo_aremove_watchers()}}, but it will not work ok when the asynch function is used directly for the reason stated perviously.

Another side note: the docs state that setting the 'local' flag makes the C-client remove the watcher "even if there is no server connection" - but really it makes the C-client remove the watcher without notifying the server at *all*, even if the connection to a server is up. (well... that's what it would do if it didn't just crash instead ;)



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)