ajp13 stuck on read

[Shinta Tjio <st...@broadjump.com>]

Hi,
We've been seeing some problems where both the Tomcat ajp13 
connector and the Apache children (using mod_jk and ajp13) 
got stuck on read. The load on the system is not too heavy,
i.e: there's only 12-20 Apache children around when we first 
saw the problem. 

We are using Tomcat 3.2.1 and Apache 1.3.14. Has anyone seen
this problem and found an explaination for it?

Tomcat's ajp13 connector stack trace looks like this:

Full thread dump:
"Thread-34" (TID:0x178d2b8, sys_thread_t:0x178d1f0, state:R, thread_t:
t@91, thr
eadID:0xea421d78, stack_bottom:0xea422000, stack_size:0x20000) prio=5

[1] java.net.SocketInputStream.socketRead(Native Method)
[2] java.net.SocketInputStream.read(SocketInputStream.java:85)
[3]
org.apache.tomcat.service.connector.TcpConnector.receiveFully(TcpConnect
or.j
ava:148)
[4]
org.apache.tomcat.service.connector.TcpConnector.receive(TcpConnector.ja
va:1
18)
[5]
org.apache.tomcat.service.connector.Ajp13ConnectorRequest.refeelReadBuff
er(A
jp13ConnectorRequest.java:288)
[6]
org.apache.tomcat.service.connector.Ajp13ConnectorRequest.doRead(Ajp13Co
nnec
torRequest.java:252)
[7]
org.apache.tomcat.service.connector.Ajp13ConnectorRequest.doRead(Ajp13Co
nnec
torRequest.java:261)
[8]
org.apache.tomcat.core.BufferedServletInputStream.doRead(BufferedServlet
Inpu
tStream.java:111)
[9]
org.apache.tomcat.core.BufferedServletInputStream.read(BufferedServletIn
putS
tream.java:137)
[10]
org.apache.tomcat.core.BufferedServletInputStream.read(BufferedServletIn
put
Stream.java:133)
[11] myservlet.process(myservlet.java:97)
[12] myservlet.doPost(myservlet.java:161)
[13] javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
[14] javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
[15]
org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:399)
[16] org.apache.tomcat.core.Handler.service(Handler.java:250)
[17]
org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:348)
[18]
org.apache.tomcat.core.ContextManager.internalService(ContextManager.jav
a:7
62)
[19]
org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)
[20]
org.apache.tomcat.service.connector.Ajp13ConnectionHandler.processConnec
tio
n(Ajp13ConnectionHandler.java:109)
[21]
org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:393
)
[22]
org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:47
5)
[23] java.lang.Thread.run(Thread.java:478)

The Apache child's process stack trace looks like this:

(gdb) where
#0  0xff218190 in _so_recv () from /usr/lib/libc.so.1
#1  0xfefefa7c in jk_tcp_socket_recvfull ()
   from /opt/apache/libexec/mod_jk.so
#2  0xfefeff4c in connection_tcp_get_message ()
   from /opt/apache/libexec/mod_jk.so
#3  0xfeff12ec in getreply () from /opt/apache/libexec/mod_jk.so
#4  0xfeff1634 in service () from /opt/apache/libexec/mod_jk.so
#5  0xfeff6d58 in jk_handler () from /opt/apache/libexec/mod_jk.so
#6  0x1f278 in ap_invoke_handler ()
#7  0x3c4e0 in process_request_internal ()
#8  0x3c564 in ap_process_request ()
#9  0x2fe8c in child_main ()
#10 0x30240 in make_child ()
#11 0x307b8 in perform_idle_server_maintenance ()
#12 0x31034 in standalone_main ()
#13 0x31998 in main ()

thanks,
shinta

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