1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.server; 18 19 import android.util.Log; 20 import android.util.LogWriter; 21 import android.util.Slog; 22 23 import com.android.internal.annotations.VisibleForTesting; 24 import com.android.server.Watchdog.HandlerChecker; 25 26 import dalvik.system.AnnotatedStackTraceElement; 27 import dalvik.system.VMStack; 28 29 import java.io.PrintWriter; 30 import java.util.List; 31 32 /** 33 * Class to give diagnostic messages for Watchdogs. 34 */ 35 class WatchdogDiagnostics { getBlockedOnString(Object blockedOn)36 private static String getBlockedOnString(Object blockedOn) { 37 return String.format("- waiting to lock <0x%08x> (a %s)", 38 System.identityHashCode(blockedOn), blockedOn.getClass().getName()); 39 } 40 getLockedString(Object heldLock)41 private static String getLockedString(Object heldLock) { 42 return String.format("- locked <0x%08x> (a %s)", System.identityHashCode(heldLock), 43 heldLock.getClass().getName()); 44 } 45 46 /** 47 * Print the annotated stack for the given thread. If the annotated stack cannot be retrieved, 48 * returns false. 49 */ 50 @VisibleForTesting printAnnotatedStack(Thread thread, PrintWriter out)51 public static boolean printAnnotatedStack(Thread thread, PrintWriter out) { 52 AnnotatedStackTraceElement stack[] = VMStack.getAnnotatedThreadStackTrace(thread); 53 if (stack == null) { 54 return false; 55 } 56 out.println(thread.getName() + " annotated stack trace:"); 57 for (AnnotatedStackTraceElement element : stack) { 58 out.println(" at " + element.getStackTraceElement()); 59 if (element.getBlockedOn() != null) { 60 out.println(" " + getBlockedOnString(element.getBlockedOn())); 61 } 62 if (element.getHeldLocks() != null) { 63 for (Object held : element.getHeldLocks()) { 64 out.println(" " + getLockedString(held)); 65 } 66 } 67 } 68 return true; 69 } 70 diagnoseCheckers(final List<HandlerChecker> blockedCheckers)71 public static void diagnoseCheckers(final List<HandlerChecker> blockedCheckers) { 72 PrintWriter out = new PrintWriter(new LogWriter(Log.WARN, Watchdog.TAG, Log.LOG_ID_SYSTEM), 73 true); 74 for (int i=0; i<blockedCheckers.size(); i++) { 75 Thread blockedThread = blockedCheckers.get(i).getThread(); 76 if (printAnnotatedStack(blockedThread, out)) { 77 continue; 78 } 79 80 // Fall back to "regular" stack trace, if necessary. 81 Slog.w(Watchdog.TAG, blockedThread.getName() + " stack trace:"); 82 StackTraceElement[] stackTrace = blockedThread.getStackTrace(); 83 for (StackTraceElement element : stackTrace) { 84 Slog.w(Watchdog.TAG, " at " + element); 85 } 86 } 87 } 88 } 89