问题描述
如果java层面发生了死锁，当我们使用jstack命令的时候其实是可以将死锁的信息给dump出来的，在dump结果的最后会有类似Found one Java-level deadlock:的关键字，接着会把发生死锁的线程的堆栈及对应的同步锁给打印出来，这次碰到一个系统就发生类似的问题，不过这个dump文档里虽然提到了如下的死锁信息：
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3 4 5 6 7 8 9 10 11 | Found one Java-level deadlock: ============================= "worker-1-thread-121": waiting to lock monitor 0x00007f3758209dc8 (object 0x0000000764cd2b20, a java.util.concurrent.ConcurrentHashMap), which is held by "HSFBizProcessor-4-thread-4" "HSFBizProcessor-4-thread-4": waiting to lock monitor 0x00007f3758289260 (object 0x000000076073ddc8, a com.alipay.cloudengine.extensions.equinox.KernelBundleClassLoader), which is held by "HSFBizProcessor-4-thread-5" "HSFBizProcessor-4-thread-5": waiting to lock monitor 0x00007f3758253420 (object 0x00000007608e6fc8, a com.alipay.cloudengine.extensions.equinox.KernelBundleClassLoader), which is held by "HSFBizProcessor-4-thread-4"
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但是我们在堆栈里搜索对应的锁的时候并没发现，也就是上面提到的
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| object 0x00000007608e6fc8 which is held by "HSFBizProcessor-4-thread-4"
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我们在HSFBizProcessor-4-thread-4这个线程的堆栈里并没有看到对应的持锁信息。
附上线程dump详情
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3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 | Found one Java-level deadlock: ============================= "worker-1-thread-121": waiting to lock monitor 0x00007f3758209dc8 (object 0x0000000764cd2b20, a java.util.concurrent.ConcurrentHashMap), which is held by "HSFBizProcessor-4-thread-4" "HSFBizProcessor-4-thread-4": waiting to lock monitor 0x00007f3758289260 (object 0x000000076073ddc8, a com.alipay.cloudengine.extensions.equinox.KernelBundleClassLoader), which is held by "HSFBizProcessor-4-thread-5" "HSFBizProcessor-4-thread-5": waiting to lock monitor 0x00007f3758253420 (object 0x00000007608e6fc8, a com.alipay.cloudengine.extensions.equinox.KernelBundleClassLoader), which is held by "HSFBizProcessor-4-thread-4" Java stack information for the threads listed above: =================================================== "worker-1-thread-121": at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:180) - waiting to lock <0x0000000764cd2b20> (a java.util.concurrent.ConcurrentHashMap) at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:455) at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:317) ...... at java.util.concurrent.FutureTask.run(FutureTask.java:138)
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