Table of Contents
本記事のOpenJDK障害は次の環境で確認しています。
$ java -version openjdk version "1.8.0_60" OpenJDK Runtime Environment (build 1.8.0_60-b24) OpenJDK 64-Bit Server VM (build 25.60-b23, mixed mode) $ uname -a Linux mimi 4.1.6-1-ARCH #1 SMP PREEMPT Mon Aug 17 08:52:28 CEST 2015 x86_64 GNU/Linux
1 プロセスのアタッチ出来ない
$ /usr/lib/jvm/java-8-openjdk/bin/jinfo -sysprops 22286 Attaching to process ID 22286, 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:497) 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)
同じ障害に遭遇した方々
- Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can’t attach to the process { solved }
- Linuxでjmap使用時に「Can’t attach to the process」と言われたら
straceで見たら、 ptrace システムコールのPTRACE_ATTACHリクエストで実行中のJavaプロセス
をアタッチしようとするところで Operation not permitted 理由に怒られた。
|$ strace -ff /usr/lib/jvm/java-8-openjdk/bin/jinfo -sysprops 22286
|（中略）
|[pid 24277] close(7) = 0
**|[pid 24277] ptrace(PTRACE_ATTACH, 22286, 0, 0) = -1 EPERM (Operation not permitted)
|[pid 24277] futex(0x7fef94008854, FUTEX_WAKE_OP_PRIVATE, 1, 1, 0x7fef94008850, {FUTEX_OP_SET, 0, FUTEX_OP_CMP_GT, 1}) = 1
|[pid 24263] <... futex resumed> ) = 0
|[pid 24277] futex(0x7fef9414b154, FUTEX_WAIT_PRIVATE, 3, NULL <unfinished ...>
|[pid 24263] futex(0x7fef94008828, FUTEX_WAKE_PRIVATE, 1) = 0
|[pid 24263] write(2, "Error attaching to process: ", 28Error attaching to process: ) = 28
|[pid 24274] futex(0x7fef940bb654, FUTEX_WAIT_BITSET_PRIVATE, 57, {29187, 107955715}, ffffffff <unfinished ...>
**|[pid 24263] write(2, "sun.jvm.hotspot.debugger.Debugge"..., 71sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process) = 71
|[pid 24263] write(2, "\n", 1
これはLinuxカーネルのセキュリティモジュール yama の制限に引掛かったのが原因です。 下記手順でこの制限を解除すれば、エラーが解消されます。
$ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
yamaによるptrace制限に関して下記が分かやすいと思います。
https://wiki.ubuntu.com/SecurityTeam/Roadmap/KernelHardening#ptrace_Protection
もっと簡単な対応方法として、sudoでrootユーザで実行すれば良いでしょう。
2 Metadata does not appear to be polymorphic
$ /usr/lib/jvm/java-8-openjdk/bin/jinfo -sysprops 22286 Attaching to process ID 22286, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.60-b23 Exception in thread "main" java.lang.reflect.InvocationTargetException 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:497) at sun.tools.jinfo.JInfo.runTool(JInfo.java:108) at sun.tools.jinfo.JInfo.main(JInfo.java:76) Caused by: java.lang.InternalError: Metadata does not appear to be polymorphic at sun.jvm.hotspot.types.basic.BasicTypeDataBase.findDynamicTypeForAddress(BasicTypeDataBase.java:278) at sun.jvm.hotspot.runtime.VirtualBaseConstructor.instantiateWrapperFor(VirtualBaseConstructor.java:102) at sun.jvm.hotspot.oops.Metadata.instantiateWrapperFor(Metadata.java:68) at sun.jvm.hotspot.memory.SystemDictionary.getSystemKlass(SystemDictionary.java:127) at sun.jvm.hotspot.runtime.VM.readSystemProperties(VM.java:879) at sun.jvm.hotspot.runtime.VM.getSystemProperties(VM.java:873) at sun.jvm.hotspot.tools.SysPropsDumper.run(SysPropsDumper.java:44) at sun.jvm.hotspot.tools.JInfo.run(JInfo.java:94) at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260) at sun.jvm.hotspot.tools.Tool.start(Tool.java:223) at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118) at sun.jvm.hotspot.tools.JInfo.main(JInfo.java:138) ... 6 more
原因はよくわからないのですが、twitter上で流れた情報 によるとJVMのdebuginfoを入れれば 問題が回避されるようです。実際に確認したところで確かに回避出来た、しかしdebuginfo禁止 の商用環境やdebuginfoが簡単に導入出来ないdistroには寂しいでしょう。
yumが使える環境は、次のように debuginfo-install で簡単にインストールが出来ます。
$ sudo debuginfo-install java-1.8.0-openjdk-devel
3 unknown CollectedHeap type
$ /usr/lib/jvm/java-8-openjdk/bin/jmap -heap 22286 Attaching to process ID 22286, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.60-b23 using thread-local object allocation. Parallel GC with 4 thread(s) Heap Configuration: MinHeapFreeRatio = 0 MaxHeapFreeRatio = 100 MaxHeapSize = 1367343104 (1304.0MB) NewSize = 455606272 (434.5MB) MaxNewSize = 455606272 (434.5MB) OldSize = 911736832 (869.5MB) NewRatio = 2 SurvivorRatio = 8 MetaspaceSize = 21807104 (20.796875MB) CompressedClassSpaceSize = 1073741824 (1024.0MB) MaxMetaspaceSize = 17592186044415 MB G1HeapRegionSize = 0 (0.0MB) Heap Usage: Exception in thread "main" java.lang.reflect.InvocationTargetException 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:497) at sun.tools.jmap.JMap.runTool(JMap.java:201) at sun.tools.jmap.JMap.main(JMap.java:130) Caused by: java.lang.RuntimeException: unknown CollectedHeap type : class sun.jvm.hotspot.gc_interface.CollectedHeap at sun.jvm.hotspot.tools.HeapSummary.run(HeapSummary.java:144) at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260) at sun.jvm.hotspot.tools.Tool.start(Tool.java:223) at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118) at sun.jvm.hotspot.tools.HeapSummary.main(HeapSummary.java:49) ... 6 more
このエラーもdebuginfoをインストールすれば、回避出来る。
↓OpenJDK7でバグ報告された記録、残念ながら WONTFIX 状態でした。