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  1. Seam 2
  2. JBSEAM-4487

Concurrent requests; one invalidates the session, results in recursive loop of session creation

    Details

    • Type: Bug
    • Status: Open (View Workflow)
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 2.1.1.GA, 2.1.2.CR1, 2.1.2.CR2, 2.1.2.GA, 2.2.0.CR1, 2.2.0.GA
    • Fix Version/s: None
    • Component/s: Core
    • Labels:
    • Environment:

      Jboss 4.2.2 with shipped Tomcat on Linux.

      Description

      I noticed that we had an massive number of sessions on one of our tomcat nodes that hosts our modest Seam app. After some investigation I discovered this in the log

      2009-11-25 17:38:02,521 INFO [org.jboss.seam.contexts.Contexts] starting up: org.jboss.seam.web.session
      2009-11-25 17:38:02,522 INFO [org.jboss.seam.contexts.Contexts] starting up: org.jboss.seam.security.identity
      2009-11-25 17:38:02,522 INFO [org.jboss.seam.contexts.Contexts] starting up: org.jboss.seam.web.session
      2009-11-25 17:38:02,522 INFO [org.jboss.seam.contexts.Contexts] starting up: org.jboss.seam.security.identity
      2009-11-25 17:38:02,522 INFO [org.jboss.seam.contexts.Contexts] starting up: org.jboss.seam.web.session

      This is repeated for thousands of lines and tomcat reports we have over 100,000 sessions (far more than the 100s we normally have). After digging around the seam code I realised that if you have two concurrent requests and one invalidates the session before the other is finished, seam goes into an recursive loop of session creation (normally ended by stack overflow). Here's a stack trace showing two recursions.

      at org.jboss.seam.Component.newInstance(Component.java:2094)
      at org.jboss.seam.contexts.Contexts.startup(Contexts.java:304)
      at org.jboss.seam.contexts.Contexts.startup(Contexts.java:278)
      at org.jboss.seam.contexts.Lifecycle.beginSession(Lifecycle.java:209)
      at org.jboss.seam.contexts.ServletLifecycle.beginSession(ServletLifecycle.java:141)
      at org.jboss.seam.servlet.SeamListener.sessionCreated(SeamListener.java:45)
      at org.apache.catalina.session.StandardSession.tellNew(StandardSession.java:397)
      at org.apache.catalina.session.StandardSession.setId(StandardSession.java:369)
      at org.apache.catalina.session.ManagerBase.createSession(ManagerBase.java:828)
      at org.apache.catalina.session.StandardManager.createSession(StandardManager.java:291)
      at org.apache.catalina.connector.Request.doGetSession(Request.java:2312)
      at org.apache.catalina.connector.Request.getSession(Request.java:2075)
      at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:833)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:545)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at com.sun.faces.context.SessionMap.getSession(ExternalContextImpl.java:1002)
      at com.sun.faces.context.SessionMap.get(ExternalContextImpl.java:962)
      at org.jboss.seam.contexts.ServerConversationContext.get(ServerConversationContext.java:110)
      at org.jboss.seam.contexts.Contexts.lookupInStatefulContexts(Contexts.java:189)
      at org.jboss.seam.Component.getInstance(Component.java:1949)
      at org.jboss.seam.Component.getInstance(Component.java:1944)
      at org.jboss.seam.Component.getInstance(Component.java:1924)
      at org.jboss.seam.Component.getInstance(Component.java:1919)
      at org.jboss.seam.security.Identity.create(Identity.java:101)
      at sun.reflect.GeneratedMethodAccessor2896.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:585)
      at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
      at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:144)
      at org.jboss.seam.Component.callComponentMethod(Component.java:2211)
      at org.jboss.seam.Component.callCreateMethod(Component.java:2134)
      at org.jboss.seam.Component.newInstance(Component.java:2094)
      at org.jboss.seam.contexts.Contexts.startup(Contexts.java:304)
      at org.jboss.seam.contexts.Contexts.startup(Contexts.java:278)
      at org.jboss.seam.contexts.Lifecycle.beginSession(Lifecycle.java:209)
      at org.jboss.seam.contexts.ServletLifecycle.beginSession(ServletLifecycle.java:141)
      at org.jboss.seam.servlet.SeamListener.sessionCreated(SeamListener.java:45)
      at org.apache.catalina.session.StandardSession.tellNew(StandardSession.java:397)
      at org.apache.catalina.session.StandardSession.setId(StandardSession.java:369)
      at org.apache.catalina.session.ManagerBase.createSession(ManagerBase.java:828)
      at org.apache.catalina.session.StandardManager.createSession(StandardManager.java:291)
      at org.apache.catalina.connector.Request.doGetSession(Request.java:2312)
      at org.apache.catalina.connector.Request.getSession(Request.java:2075)
      at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:833)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:545)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
      at com.sun.faces.context.SessionMap.getSession(ExternalContextImpl.java:1002)
      at com.sun.faces.context.SessionMap.get(ExternalContextImpl.java:962)
      at org.jboss.seam.contexts.ServerConversationContext.get(ServerConversationContext.java:110)
      at org.jboss.seam.contexts.Contexts.lookupInStatefulContexts(Contexts.java:189)
      at org.jboss.seam.Component.getInstance(Component.java:1949)
      at org.jboss.seam.Component.getInstance(Component.java:1944)
      at org.jboss.seam.Component.getInstance(Component.java:1924)
      at org.jboss.seam.Component.getInstance(Component.java:1919)
      at org.jboss.seam.security.Identity.create(Identity.java:101)
      at sun.reflect.GeneratedMethodAccessor2896.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:585)
      at org.jboss.seam.util.Reflections.invoke(Reflections.java:22)
      at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:144)
      at org.jboss.seam.Component.callComponentMethod(Component.java:2211)
      at org.jboss.seam.Component.callCreateMethod(Component.java:2134)
      at org.jboss.seam.Component.newInstance(Component.java:2094)

      This problem is partially documented here - https://jira.jboss.org/jira/browse/JBSEAM-2888, unfortunately this bugfix didn't solve the root cause of the problem.

      The problem is caused by the SessionMap used by ServerConversationContext. Internally the session map uses HttpServletRequest.getSession(true) to retrieve the session, which creates a new session if the one defined on the HttpServletRequest is invalid or null. Unfortunately, when the new session is created session listeners are informed before the session has been set on the HttpServletRequest. Seam is one of these session listeners and creates a new Identity on session creation, which in turn accesses the SessionMap, still before the new Session has been set on the request. This leads to an infinite recursive loop.

      The SessionMap used is returned by externalContext.getSessionMap(). One solution could be to implement our own SessionMap that doesn't attempt to create a new session if the current session is invalid or null, although I've no idea how this would impact on other Seam code.

      In windows we can recreate the problem by having a button that calls #

      {session.invalidate}

      . Another more realistic way to recreate the problem is to have one tab performing a long running search and logging out using identity.logout in some other tab. When the search completes the error occurs.

      We've tried the above in Linux, but it doesn't recreate the problem. I suspect this is due to Windows and Linux returning the list of components in a different order, probably due to the underlying filesystem.

      We are using seam 2.1.1.GA. I've looked at the source code for the latest release and it appears that the problem will still occur due to use of SessionMap.

      Out current workaround is to override Identity.create and add a ThreadLocal that counts recursive calls. If more then two recursive calls are detected an IllegalStateException is thrown. This definitely isn't a permanent solution, but stops our server creating 100,000 sessions.

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              • Assignee:
                Unassigned
                Reporter:
                davidatkinsuk dave atkins
              • Votes:
                7 Vote for this issue
                Watchers:
                9 Start watching this issue

                Dates

                • Created:
                  Updated: