Win2kSP4, Apache-2.0.49 + Tomcat-5.0.27 + mod_jk2-2.0.43 - Memory Reference Error

OS: Windows 2000, Service Pack 4
Apache ver.: 2.0.49
Tomcat ver.: 5.0.27
mod_jk2 ver.: 2.0.43

We have a server set up to forward requests through Apache to Tomcat
using mod_jk2. The setup works, except that periodically it will throw
an error as follows on the server:

-
Application popup: Apache.exe - Application Error : The instruction at
"0x6eec7826" referenced memory at "0x00000000". The memory could not
be "read".
-

On the user end, the web app is not interrupted when this happens.
In the mod_jk2 error log, the following lines appear when this error
does:

-
[Wed Jul 21 10:07:21 2004] (error ) [jk_worker_ajp13.c (546)]
ajp13.service() ajpGetReply recoverable error 3
[Wed Jul 21 10:07:21 2004] (error ) [jk_worker_ajp13.c (546)]
ajp13.service() ajpGetReply recoverable error 3
[Wed Jul 21 10:07:21 2004] (error ) [jk_worker_ajp13.c (648)]
ajp13.service() Error forwarding ajp13:localhost:8009 1 0
[Wed Jul 21 10:07:21 2004] (error ) [mod_jk2.c (752)]
mod_jk2.handler() Error connecting to tomcat 3, status 200
-

We have looked extensively at the access log and a tomcat's logs but
have not been able to to find any related activity.

Oddly, in the SSL.log the following line appears seemingly randomly
(not obviously related to the error pop-ups):

-
mod_jk: Error flushing
-

We don't know if this is related or not. It appears just like that, no
timestamp or anything. We are not using mod_jk, it is not included.

We've serached in Google, Google groups, and the bug database
extensively but have found similar but not identical complaints,
none of which are (publicly) resolved anyway.

On a test server we reduced the occurence of the error by fiddling
with configuration files. It seems to have eliminated the error, but
does not get much traffic so it may just have been reduced. We have
duplicated the settings on the production server, and we did manage
to seemingly reduce the occurence of the error but did not eliminate
it. It still pops up hundreds of times a day.

I'm assuming that we have some kind of misconfiguration, but after
weeks of searching the web and reading the (rather spare)
documentation, we haven't been able to determine what the problem
is. Our relevant config files are attached below.

Does anyone have any pointers for us? Let me if I've left out some
important config info.

Thanks,
Noah


----------------------------------------------------------------------------
Config Files:
----------------------------------------------------------------------------


httpd.conf:
----------------------------------------------------------------------------
The only relevant part as far as I know. It listens on port 443.
We needed Win32DisableAcceptEx to get rid of a different error.

Win32DisableAcceptEx

<IfDefine SSL>
<VirtualHost 192.168.1.1:443>
ServerName example.server.com

<Directory />
Options FollowSymLinks
AllowOverride none
</Directory>

SSLEngine on
SSLCertificateFile conf/ssl.crt/entrustexampleserver.crt
SSLCertificateChainFile conf/ssl.crt/entrustchaincert.crt
SSLCertificateKeyFile conf/ssl.key/example_server_com.key

<IfModule mod_jk2.c>
<Location "/jkstatus">
JkUriSet group status:
Order Deny,Allow
Deny from all
Allow from 192.168.1.1
</Location>
<Location "/app/*">
Redirect permanent /app/login.jsp
https://example.server.com/index.html
JkUriSet worker ajp13:localhost:8009
</Location>
</IfModule>

</VirtualHost>
</IfDefine>
----------------------------------------------------------------------------


server.xml:
----------------------------------------------------------------------------
These are the only connectors:

<Connector
port="7001" maxThreads="150" minSpareThreads="25"
maxSpareThreads="75"
enableLookups="false" redirectPort="8443" acceptCount="100"
debug="0" connectionTimeout="20000"
disableUploadTimeout="true" />

<Connector port="8009" secure="true" scheme="https"
enableLookups="false" debug="0"
protocol="AJP/1.3" />
----------------------------------------------------------------------------


workers2.properties:
----------------------------------------------------------------------------
[config:]
debug=0
debugEnv=0

[logger]
level=error

[logger.file:0]
ver=3
file=D:/apache2/logs/mod_jk2.log
level=error

[workerEnv:]
debug=0
timing=0
logger=logger.file:0

[uriMap:]
debug=0

[shm:]
debug=0
disabled=0
file=logs/mod_jk2.shm

[status:]
debug=0
disabled=0

[ajp13:localhost:8009]
channel=channel.socket:localhost:8009

[channel.socket:localhost:8009]
port=8009
host=127.0.0.1
ver=0
debug=0
disabled=0
nodelay=0
timeout=60
graceful=0
keepalive=0