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From "Matthew Sweet (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (AXIS2C-1476) Memory leak when loosing connections
Date Wed, 14 Mar 2012 11:16:38 GMT

    [ https://issues.apache.org/jira/browse/AXIS2C-1476?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13229132#comment-13229132
] 

Matthew Sweet commented on AXIS2C-1476:
---------------------------------------

Firstly thanks to Sam for finding this - we've just tripped over it too and he has saved us
hours of examining code.

There is an underlying problem here. read has been declared as a size_t, rather than a long.
size_t is unsigned.

In error cases ap_get_client_block() returns negative values.

Better than looking for 0xFFFFFFFF would be to declare read as being a long, as this will
defend against people returning other negative values.

Another possible enhancement would be to remember that a negative value has been returned,
and do something to "close" the stream permanently.
                
> Memory leak when loosing connections
> ------------------------------------
>
>                 Key: AXIS2C-1476
>                 URL: https://issues.apache.org/jira/browse/AXIS2C-1476
>             Project: Axis2-C
>          Issue Type: Bug
>          Components: httpd module
>    Affects Versions: 1.6.0
>         Environment: Windows 7 64-bit, Visual Studio 2010
>            Reporter: Sam Carleton
>            Priority: Blocker
>              Labels: ap_get_client_block, apache2_stream_read
>             Fix For: 1.7.0
>
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> I was load testing my apache code today by starting 50 clients which all start in a slide
show mode, pooling the server at least every 5 seconds.  I have a manager program that starts
the clients and does does an abort of the processes when I want to close them.  That is the
secret, the abort...
> I was watching memory usage while it ran, and all was fine, Apache held steady at around
55 megs.  Once I killed the 50 processes, all at the EXACT same time, well milliseconds apart,
the memory usage sky rocketed.  When I broke the code, I was in the mod_axis2::apache2_stream_read
function.
> It turns out that ap_get_client_block(...) was returning 0xFFFFFFFF to the read variable:
> read = ap_get_client_block(stream_impl->request, (char *) buffer + len,
>                            count - len);
> if (read > 0)
> It turns out that read is unsigned, so the 0xFFFFFFFF is NOT negative, so I changed the
code to read:
> if (read > 0 && read != 0xFFFFFFFF)
> All is well after the minor addition!

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