Andreas Gampe | 544416e | 2018-01-26 11:39:46 -0800 | [diff] [blame] | 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 { |
| 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 | |
| 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 |
| 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 | |
| 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 | } |