使用Java监控工具出现 Can't attach to the process

问题重现

➜ jinfo -flags 3032

Attaching to process ID 3032, please wait...

Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process

sun.jvm.hotspot.debugger.DebuggerException: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.execute(LinuxDebuggerLocal.java:163)

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach(LinuxDebuggerLocal.java:278)

at sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:671)

at sun.jvm.hotspot.HotSpotAgent.setupDebuggerLinux(HotSpotAgent.java:611)

at sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:337)

at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:304)

at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:140)

at sun.jvm.hotspot.tools.Tool.start(Tool.java:185)

at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)

at sun.jvm.hotspot.tools.JInfo.main(JInfo.java:138)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:483)

at sun.tools.jinfo.JInfo.runTool(JInfo.java:108)

at sun.tools.jinfo.JInfo.main(JInfo.java:76)

Caused by: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach0(Native Method)

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.access$100(LinuxDebuggerLocal.java:62)

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$1AttachTask.doit(LinuxDebuggerLocal.java:269)

at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal$LinuxDebuggerLocalWorkerThread.run(LinuxDebuggerLocal.java:138)

解决办法

1	echo 0 \| sudo tee /proc/sys/kernel/yama/ptrace_scope

再次执行时就可以得到结果了

➜ jinfo -flags 3032

Attaching to process ID 3032, please wait...

Debugger attached successfully.

Server compiler detected.

JVM version is 25.5-b02

Non-default VM flags: -XX:InitialHeapSize=41943040 -XX:MaxHeapSize=536870912 -XX:MaxNewSize=178782208 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=1572864 -XX:OldSize=40370176 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC

Command line: -Dosgi.requiredJavaVersion=1.6 -XX:MaxPermSize=256m -Xms40m -Xmx512m

原因

这是因为新版的Linux系统加入了 ptrace-scope 机制. 这种机制为了防止用户访问当前正在运行的进程的内存和状态, 而一些调试软件本身就是利用 ptrace 来进行获取某进程的内存状态的(包括GDB),所以在新版本的Linux系统, 默认情况下不允许再访问了. 可以临时开启. 如:

1	echo 0 > /proc/sys/kernel/yama/ptrace_scope

永久写到文件来持久化:

emacs /etc/sysctl.d/10-ptrace.conf

添加或修改为以下这一句:(0:允许, 1:不允许)

kernel.yama.ptrace_scope = 0

转载于:https://www.cnblogs.com/duanxz/p/10240899.html