AFAIK, a thread will only release the lock in the closest synchronization scope.
If you can make sure that the UCL itself is the last lock before entering ULR, then it should IMHO work. Since we are not in control of loadClassInternal, but of loadClass, there is the chance that this will do as wished. CGJ -----Ursprüngliche Nachricht----- Von: marc fleury [mailto:[EMAIL PROTECTED]] Gesendet: Dienstag, 23. April 2002 03:07 An: Dave Smith Cc: lsanders; Jboss-Development@Lists. Sourceforge. Net Betreff: RE: [JBoss-dev] Workaround for CL stuff Solution: When a thread goes through loadClass, in the ULR we "lock" with a field that tracks the thread. Another thread comes in, reaches ULR, we sync on the calling CL (we know it) we wait, this releases the lock, we keep track of the CL as part of this "load". The first thread will always find a CL as no CL can be locked for ever, since the thread that would reach the ULR would wait. First thread always finishes (with reentrancy so the count must go on and we track the fact that it is the same thread). When count reaches 0 we get the set of CL that were touched by this thread (i.e. the set of CLs that had threads in it) and we notifyAll on each element of the set, start this again. Done (afaict), I will try to apply it to the stack trace below. |I brought this thing back to life and passed the URL of the orginal sun |bug that they rejected. Here is a quick stack trace of the deadlock. |Note that you should start jboss with the -Xdebug options so it shows |you what objects that it is trying to lock. See below for my orginal |post | | |"CCRAPoll" prio=5 tid=0x8184f58 nid=0x64ec waiting for monitor entry |[0xbb7fe000..0xbb7ffad8] | at java.lang.ClassLoader.loadClass(ClassLoader.java:288) | - waiting to lock <43a2c508> (a |org.jboss.mx.loading.UnifiedClassLoader) | at |org.jboss.mx.loading.UnifiedClassLoader.loadClassLocally(UnifiedCla ssLoader.java:180) | at |org.jboss.mx.loading.UnifiedLoaderRepository.loadClass(UnifiedLoade rRepository.java:178) This one would reach ULR and lock the ULR, see below for lock <43a2c508> NOT being locked. | at |org.jboss.mx.loading.UnifiedClassLoader.loadClass(UnifiedClassLoade |r.java:217) | at java.lang.ClassLoader.loadClass(ClassLoader.java:255) | at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315) | - locked <43eefa48> (a org.jboss.mx.loading.UnifiedClassLoader) | at |com.entrust.toolkit.PKCS7EncodeStream.e(PKCS7EncodeStream.java) | at |com.entrust.toolkit.PKCS7EncodeStream.f(PKCS7EncodeStream.java) | at |com.entrust.toolkit.PKCS7EncodeStream.write(PKCS7EncodeStream.java) | at com.candata.gateway.Encryption.Sign(Unknown Source) | - locked <43f0c6a0> (a com.candata.gateway.Encryption) | at com.candata.gateway.Encryption.createMsg(Unknown Source) | at com.candata.gateway.CCRAAbstract.postMsg(Unknown Source) | at com.candata.gateway.CCRAAbstract.recvMsg(Unknown Source) | at com.candata.gateway.CCRAPoll.run(Unknown Source) | at java.lang.Thread.run(Thread.java:484) | | |"Thread-20" prio=5 tid=0x81821a8 nid=0x64f9 waiting for monitor entry |[0xbe7fe000..0xbe7ffad8] | at java.lang.ClassLoader.loadClass(ClassLoader.java:288) | - waiting to lock <43eefa48> (a |org.jboss.mx.loading.UnifiedClassLoader) | at |org.jboss.mx.loading.UnifiedClassLoader.loadClassLocally(UnifiedCla ssLoader.java:180) | at |org.jboss.mx.loading.UnifiedLoaderRepository.loadClass(UnifiedLoade rRepository.java:178) thread 2 reaches here and sees a ULR under usage. It waits on the calling UCL (which we know it is passed) and THEREFORE UNLOCKS <43a2c508>. Done marcf | at |org.jboss.mx.loading.UnifiedClassLoader.loadClass(UnifiedClassLoade |r.java:217) | at java.lang.ClassLoader.loadClass(ClassLoader.java:255) | at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:315) | - locked <43a2c508> (a org.jboss.mx.loading.UnifiedClassLoader) | at java.lang.Class.forName0(Native Method) | at java.lang.Class.forName(Class.java:195) | at |javax.security.auth.login.LoginContext.invoke(LoginContext.java:626) | at |javax.security.auth.login.LoginContext.access$000(LoginContext.java:129) | at |javax.security.auth.login.LoginContext$4.run(LoginContext.java:599) | at java.security.AccessController.doPrivileged(Native Method) | at |javax.security.auth.login.LoginContext.invokeModule(LoginContext.java:596) | at |javax.security.auth.login.LoginContext.login(LoginContext.java:523) | at com.candata.util.beans.CandataClientLogin.login(Unknown |Source) | at com.candata.bbxinterface.BbxJavaInvoker.login(Unknown Source) | at com.candata.bbxinterface.BbxWrapper.run(Unknown Source) | at java.lang.Thread.run(Thread.java:484) marcf _______________________________________________ Jboss-development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development _______________________________________________ Jboss-development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development
