jstack发现死锁,求问一下这种死锁可能的原理?

[逗泥丸的平方]

Found one Java-level deadlock:
=============================
"pool-168-thread-1":
waiting for ownable synchronizer 0x0000000798eb5dc0, (a java.util.concurrent.locks.ReentrantLock$NonfairSync),
which is held by "pool-1-thread-4"
"pool-1-thread-4":
waiting for ownable synchronizer 0x0000000798f5a9a0, (a java.util.concurrent.locks.ReentrantLock$NonfairSync),
which is held by "pool-1-thread-8"
"pool-1-thread-8":
waiting for ownable synchronizer 0x0000000798eb5dc0, (a java.util.concurrent.locks.ReentrantLock$NonfairSync),
which is held by "pool-1-thread-4"

Java stack information for the threads listed above:
===================================================
"pool-168-thread-1":
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000798eb5dc0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Unknown Source)
at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(Unknown Source)
at java.util.concurrent.locks.ReentrantLock.lock(Unknown Source)
...
at java.lang.Thread.run(Unknown Source)
"pool-1-thread-4":
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000798f5a9a0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Unknown Source)
at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(Unknown Source)
at java.util.concurrent.locks.ReentrantLock.lock(Unknown Source)
...
at java.lang.Thread.run(Unknown Source)
"pool-1-thread-8":
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000798eb5dc0> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
at java.util.concurrent.locks.LockSupport.park(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(Unknown Source)
at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(Unknown Source)
at java.util.concurrent.locks.ReentrantLock.lock(Unknown Source)
...
at java.lang.Thread.run(Unknown Source)

Found 1 deadlock.


隐去了部分业务代码的栈信息,用... 代替了

没有看到held的情况,都是parking to wait for .. 被定位了deadlock,而且是三个线程,是退出时机的问题吗?

不是太理解,求大佬指教

[ml_dark]

waiting for ownable synchronizer 0x0000000798eb5dc0，which is held by "pool-1-thread-4" ============== 代码因为没有异常释放锁，ReentrantLock对象没有unlock

[逗泥丸的平方]

引用 1 楼 ml_dark 的回复:

waiting for ownable synchronizer 0x0000000798eb5dc0，which is held by "pool-1-thread-4"
==============
代码因为没有异常释放锁，ReentrantLock对象没有unlock

后来发现了.. 有一个线程拿了两个锁.....