[jira] [Updated] (AVRO-1165) Avro-C: Memory leak in value iface containing AVRO_LINK.

["Vivek Nadkarni (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AVRO-1165?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vivek Nadkarni updated AVRO-1165:
---------------------------------

    Attachment: AVRO-1165-TEST.patch

This patch (AVRO-1165-TEST.patch) provides a test that shows the memory leak, when the test program in the patch is run through valgrind. 

To validate AVRO-1165, run this test program through valgrind before and after applying the AVRO-1165-FIX.patch. Before the applying the fix valgrind will show memory leaks, and after the fix it will not.

The specific valgrind commandline to use from the avro-trunk/lang/c/tests directory is: valgrind -v --track-origins=yes --leak-check=full --show-reachable = yes ../build/tests/test_avro_1165


                
> Avro-C: Memory leak in value iface containing AVRO_LINK.
> --------------------------------------------------------
>
>                 Key: AVRO-1165
>                 URL: https://issues.apache.org/jira/browse/AVRO-1165
>             Project: Avro
>          Issue Type: Bug
>          Components: c
>    Affects Versions: 1.7.1
>         Environment: Ubuntu Linux 11.10
>            Reporter: Vivek Nadkarni
>             Fix For: 1.7.2
>
>         Attachments: AVRO-1165-TEST.patch
>
>   Original Estimate: 24h
>  Remaining Estimate: 24h
>
> A memory leak can be seen when the following matched pair of commands is called, using a schema containing an AVRO_LINK. This pair of commands constructs a class (value iface) from a schema and then destroys the constructed class.
>     record_class = avro_generic_class_from_schema( schema );
>     avro_value_iface_decref( record_class );
> If schema contains an AVRO_LINK, then avro_generic_class_from_schema() calls avro_generic_link_class(), which calls avro_schema_incref() on the AVRO_LINK target schema and assigns the target schema pointer to the iface->schema.
> When we subsequently call avro_value_iface_decref() to deallocate the class, this function calls avro_generic_link_decref_iface(), which frees the memory for the link interface without calling avro_schema_decref() on the target schema pointed to by iface->schema.
> Thus the memory of the target schema is leaked when we create and destroy a value interface for an AVRO_LINK. 
> Calling avro_schema_decref() on the the target schema (iface->schema) before calling avro_freet() on the iface fixes this memory leak.
> Note: The pair of commands shown above results in a memory leak, when we create and destroy a value interface from *any* schema containing an AVRO_LINK, regardless of whether it is recursive or not. There is a separate issue regarding memory leaks with recursive schemas described in AVRO-766. The fix for this issue can only be tested with non-recursive schemas containing AVRO_LINKs until AVRO-766 is fixed.

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