PaperMC/Spigot-API-Patches/0129-Remove-deadlock-risk-in-firing-async-events.patch
Shane Freeder 7e8ae207bd
Updated Upstream (Bukkit/CraftBukkit/Spigot)
Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Bukkit Changes:
e99c9444 Add Plugin Chunk Ticket API
6a235f06 Fix incorrect nullability annotations for PlayerJoinEvent's join message

CraftBukkit Changes:
5f889388 Tweak build expiration to 7 days
572c02b0 MC-155077, SPIGOT-5113: EntityTracker desync
7ad3a1f4 SPIGOT-5146: BlockDataMeta does not work
60860983 SPIGOT-5155: Setting EntityExplodeEvent yield to 0 still causes blocks to drop
087a2cf4 Print number of force loaded chunks per plugin in crash reports
07b5b06d Add Plugin Chunk Ticket API
7ffb2a27 SPIGOT-5149: resetRecipes does nothing
a2275f19 SPIGOT-5141: World.generateTree() causes ClassCastException with huge mushrooms
31d4a777 SPIGOT-5142: Ignore invalid firework effects

Spigot Changes:
5e4e7f32 BUILDTOOLS-471: Rebuild patches
6e944739 SPIGOT-5159: Raider activation range overridden by Monster range
2019-07-11 17:59:21 +01:00

142 lines
5.9 KiB
Diff

From e724746a98cf149f377d9a442782dc448abb8405 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 9 Sep 2018 00:32:05 -0400
Subject: [PATCH] Remove deadlock risk in firing async events
The PluginManager incorrectly used synchronization on firing any event
that was marked as synchronous.
This synchronized did not even protect any concurrency risk as
handlers were already thread safe in terms of mutations during event
dispatch.
The way it was used, has commonly led to deadlocks on the server,
which results in a hard crash.
This change removes the synchronize and adds some protection around enable/disable
diff --git a/src/main/java/org/bukkit/entity/Entity.java b/src/main/java/org/bukkit/entity/Entity.java
index adca48f1..2d3cee14 100644
--- a/src/main/java/org/bukkit/entity/Entity.java
+++ b/src/main/java/org/bukkit/entity/Entity.java
@@ -28,7 +28,7 @@ import org.jetbrains.annotations.Nullable;
*/
public interface Entity extends Metadatable, CommandSender, Nameable, PersistentDataHolder {
- /**
+ /*
* Gets the entity's current position
*
* @return a new copy of Location containing the position of this entity
diff --git a/src/main/java/org/bukkit/plugin/SimplePluginManager.java b/src/main/java/org/bukkit/plugin/SimplePluginManager.java
index 132c861c..d0e735bc 100644
--- a/src/main/java/org/bukkit/plugin/SimplePluginManager.java
+++ b/src/main/java/org/bukkit/plugin/SimplePluginManager.java
@@ -399,7 +399,7 @@ public final class SimplePluginManager implements PluginManager {
* @return true if the plugin is enabled, otherwise false
*/
@Override
- public boolean isPluginEnabled(@Nullable Plugin plugin) {
+ public synchronized boolean isPluginEnabled(@Nullable Plugin plugin) { // Paper - synchronize
if ((plugin != null) && (plugins.contains(plugin))) {
return plugin.isEnabled();
} else {
@@ -408,7 +408,7 @@ public final class SimplePluginManager implements PluginManager {
}
@Override
- public void enablePlugin(@NotNull final Plugin plugin) {
+ public synchronized void enablePlugin(@NotNull final Plugin plugin) { // Paper - synchronize
if (!plugin.isEnabled()) {
List<Command> pluginCommands = PluginCommandYamlParser.parse(plugin);
@@ -446,7 +446,7 @@ public final class SimplePluginManager implements PluginManager {
}
@Override
- public void disablePlugin(@NotNull final Plugin plugin, boolean closeClassloader) {
+ public synchronized void disablePlugin(@NotNull final Plugin plugin, boolean closeClassloader) { // Paper - synchronize
// Paper end - close Classloader on disable
if (plugin.isEnabled()) {
try {
@@ -515,6 +515,7 @@ public final class SimplePluginManager implements PluginManager {
defaultPerms.get(false).clear();
}
}
+ private void fireEvent(Event event) { callEvent(event); } // Paper - support old method incase plugin uses reflection
/**
* Calls an event with the given details.
@@ -525,25 +526,13 @@ public final class SimplePluginManager implements PluginManager {
*/
@Override
public void callEvent(@NotNull Event event) {
- if (event.isAsynchronous()) {
- if (Thread.holdsLock(this)) {
- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from inside synchronized code.");
- }
- if (server.isPrimaryThread()) {
- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from primary server thread.");
- }
- fireEvent(event);
- } else {
- if (!server.isPrimaryThread()) {
- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from another thread.");
- }
- synchronized (this) {
- fireEvent(event);
- }
+ // Paper - replace callEvent by merging to below method
+ if (event.isAsynchronous() && server.isPrimaryThread()) {
+ throw new IllegalStateException(event.getEventName() + " may only be triggered asynchronously.");
+ } else if (!event.isAsynchronous() && !server.isPrimaryThread()) {
+ throw new IllegalStateException(event.getEventName() + " may only be triggered synchronously.");
}
- }
- private void fireEvent(@NotNull Event event) {
HandlerList handlers = event.getHandlers();
RegisteredListener[] listeners = handlers.getRegisteredListeners();
diff --git a/src/test/java/org/bukkit/plugin/PluginManagerTest.java b/src/test/java/org/bukkit/plugin/PluginManagerTest.java
index 17dbe913..bae26ce7 100644
--- a/src/test/java/org/bukkit/plugin/PluginManagerTest.java
+++ b/src/test/java/org/bukkit/plugin/PluginManagerTest.java
@@ -17,7 +17,7 @@ public class PluginManagerTest {
private static final PluginManager pm = TestServer.getInstance().getPluginManager();
private final MutableObject store = new MutableObject();
-
+/* // Paper start - remove unneeded test
@Test
public void testAsyncSameThread() {
final Event event = new TestEvent(true);
@@ -28,14 +28,14 @@ public class PluginManagerTest {
return;
}
throw new IllegalStateException("No exception thrown");
- }
+ }*/ // Paper end
@Test
public void testSyncSameThread() {
final Event event = new TestEvent(false);
pm.callEvent(event);
}
-
+/* // Paper start - remove unneeded test
@Test
public void testAsyncLocked() throws InterruptedException {
final Event event = new TestEvent(true);
@@ -127,7 +127,7 @@ public class PluginManagerTest {
if (store.value == null) {
throw new IllegalStateException("No exception thrown");
}
- }
+ } */ // Paper
@Test
public void testRemovePermissionByNameLower() {
--
2.22.0