JDK1.6+Tomcat6出现挂死的问题

项目中使用的是jdk1.6.0_13和Tomcat6.0.18，使用ssh框架，系统一直稳定运行，最近突然出现tomcat挂死的问题，现象是访问页面时浏览器一直处于等待状态，查看服务器的tomcat进程貌似一切正常，使用jstack打印不了，必须使用jstack -F pid才能打出有限的信息，使用jvisualvm等都连不上（已经配置好启动参数了），感觉好像是GC线程挂死了，导致其他java线程处于阻塞状态，请各位高人看看是否遇到过或者是否有解决的思路，不胜感激。 
Deadlock Detection:
 No deadlocks found.
 Thread 26457: (state = IN_NATIVE)
  - java.lang.UNIXProcess.forkAndExec(byte[], byte[], int, byte[], int, byte[], boolean, java.io.FileDescriptor, java.io.FileDescriptor, java.io.FileDescriptor) @bci=0 (Interpreted frame)
  - java.lang.UNIXProcess.access$500(java.lang.UNIXProcess, byte[], byte[], int, byte[], int, byte[], boolean, java.io.FileDescriptor, java.io.FileDescriptor, java.io.FileDescriptor) @bci=18 (Interpreted frame)
  - java.lang.UNIXProcess$1$1.run() @bci=93 (Interpreted frame)
 Thread 22531: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 22530: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 22529: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
Thread 22509: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 22508: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 22507: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 19356: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 19355: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
 Thread 19354: (state = BLOCKED)
  - java.lang.Object.wait(long) @bci=0 (Interpreted frame)
  - com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run() @bci=34, line=534 (Compiled frame)
Thread 6523: (state = BLOCKED)
  - sun.misc.Unsafe.park(boolean, long) @bci=0 (Interpreted frame)
  - java.util.concurrent.locks.LockSupport.parkNanos(java.lang.Object, long) @bci=20 (Interpreted frame)
  - java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(java.util.concurrent.SynchronousQueue$TransferStack$SNode, boolean, long) @bci=174 (Compiled frame)
  - java.util.concurrent.SynchronousQueue$TransferStack.transfer(java.lang.Object, boolean, long) @bci=102 (Interpreted frame)
  - java.util.concurrent.SynchronousQueue.poll(long, java.util.concurrent.TimeUnit) @bci=11 (Interpreted frame)
  - java.util.concurrent.ThreadPoolExecutor.getTask() @bci=62 (Interpreted frame)
  - java.util.concurrent.ThreadPoolExecutor$Worker.run() @bci=18 (Interpreted frame)
  - java.lang.Thread.run() @bci=11 (Interpreted frame)