124 lines
5.4 KiB
Diff
124 lines
5.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Aikar <aikar@aikar.co>
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Date: Sun, 9 Sep 2018 00:32:05 -0400
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Subject: [PATCH] Remove deadlock risk in firing async events
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The PluginManager incorrectly used synchronization on firing any event
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that was marked as synchronous.
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This synchronized did not even protect any concurrency risk as
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handlers were already thread safe in terms of mutations during event
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dispatch.
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The way it was used, has commonly led to deadlocks on the server,
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which results in a hard crash.
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This change removes the synchronize and adds some protection around enable/disable
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diff --git a/src/main/java/org/bukkit/plugin/SimplePluginManager.java b/src/main/java/org/bukkit/plugin/SimplePluginManager.java
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index c43d819bae5bc51bcf57a575bc22aee9d501c562..3457dd6a86f927dd38edd200121aad5364d8abd5 100644
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--- a/src/main/java/org/bukkit/plugin/SimplePluginManager.java
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+++ b/src/main/java/org/bukkit/plugin/SimplePluginManager.java
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@@ -472,7 +472,7 @@ public final class SimplePluginManager implements PluginManager {
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* @return true if the plugin is enabled, otherwise false
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*/
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@Override
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- public boolean isPluginEnabled(@Nullable Plugin plugin) {
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+ public synchronized boolean isPluginEnabled(@Nullable Plugin plugin) { // Paper - synchronize
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if ((plugin != null) && (plugins.contains(plugin))) {
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return plugin.isEnabled();
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} else {
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@@ -481,7 +481,7 @@ public final class SimplePluginManager implements PluginManager {
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}
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@Override
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- public void enablePlugin(@NotNull final Plugin plugin) {
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+ public synchronized void enablePlugin(@NotNull final Plugin plugin) { // Paper - synchronize
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if (!plugin.isEnabled()) {
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List<Command> pluginCommands = PluginCommandYamlParser.parse(plugin);
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@@ -524,7 +524,7 @@ public final class SimplePluginManager implements PluginManager {
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// Paper end
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@Override
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- public void disablePlugin(@NotNull final Plugin plugin) {
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+ public synchronized void disablePlugin(@NotNull final Plugin plugin) { // Paper - synchronize
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if (plugin.isEnabled()) {
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try {
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plugin.getPluginLoader().disablePlugin(plugin);
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@@ -593,6 +593,7 @@ public final class SimplePluginManager implements PluginManager {
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defaultPerms.get(false).clear();
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}
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}
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+ private void fireEvent(Event event) { callEvent(event); } // Paper - support old method incase plugin uses reflection
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/**
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* Calls an event with the given details.
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@@ -601,23 +602,13 @@ public final class SimplePluginManager implements PluginManager {
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*/
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@Override
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public void callEvent(@NotNull Event event) {
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- if (event.isAsynchronous()) {
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- if (Thread.holdsLock(this)) {
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- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from inside synchronized code.");
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- }
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- if (server.isPrimaryThread()) {
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- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from primary server thread.");
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- }
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- } else {
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- if (!server.isPrimaryThread()) {
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- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from another thread.");
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- }
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+ // Paper - replace callEvent by merging to below method
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+ if (event.isAsynchronous() && server.isPrimaryThread()) {
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+ throw new IllegalStateException(event.getEventName() + " may only be triggered asynchronously.");
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+ } else if (!event.isAsynchronous() && !server.isPrimaryThread()) {
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+ throw new IllegalStateException(event.getEventName() + " may only be triggered synchronously.");
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}
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- fireEvent(event);
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- }
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-
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- private void fireEvent(@NotNull Event event) {
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HandlerList handlers = event.getHandlers();
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RegisteredListener[] listeners = handlers.getRegisteredListeners();
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diff --git a/src/test/java/org/bukkit/plugin/PluginManagerTest.java b/src/test/java/org/bukkit/plugin/PluginManagerTest.java
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index f188cd4f3b07027c30d41f1162db77a506b7b6bb..1941c9f49e9514c1236c5f4ea9f7af47f7be85c5 100644
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--- a/src/test/java/org/bukkit/plugin/PluginManagerTest.java
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+++ b/src/test/java/org/bukkit/plugin/PluginManagerTest.java
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@@ -17,7 +17,7 @@ public class PluginManagerTest {
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private static final PluginManager pm = TestServer.getInstance().getPluginManager();
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private final MutableObject store = new MutableObject();
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-
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+/* // Paper start - remove unneeded test
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@Test
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public void testAsyncSameThread() {
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final Event event = new TestEvent(true);
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@@ -28,14 +28,14 @@ public class PluginManagerTest {
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return;
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}
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throw new IllegalStateException("No exception thrown");
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- }
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+ }*/ // Paper end
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@Test
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public void testSyncSameThread() {
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final Event event = new TestEvent(false);
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pm.callEvent(event);
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}
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-
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+/* // Paper start - remove unneeded test
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@Test
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public void testAsyncLocked() throws InterruptedException {
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final Event event = new TestEvent(true);
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@@ -129,7 +129,7 @@ public class PluginManagerTest {
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if (store.value == null) {
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throw new IllegalStateException("No exception thrown");
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}
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- }
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+ } */ // Paper
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@Test
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public void testRemovePermissionByNameLower() {
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