papermc/Spigot-API-Patches/0129-Remove-deadlock-risk-in-firing-async-events.patch
Aikar 57dd397155
Updated Upstream (Bukkit/CraftBukkit)
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:
b999860d SPIGOT-2304: Add LootGenerateEvent

CraftBukkit Changes:
77fd87e4 SPIGOT-2304: Implement LootGenerateEvent
a1a705ee SPIGOT-5566: Doused campfires & fires should call EntityChangeBlockEvent
41712edd SPIGOT-5707: PersistentDataHolder not Persistent on API dropped Item
2020-05-01 18:03:57 -04:00

140 lines
5.8 KiB
Diff

From 6e4fb0cc9482d789961ef8e386fb3fa8d6f17a4c 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 a8dbf282d..b4069dbf3 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 8bb24f734..8355f9f0e 100644
--- a/src/main/java/org/bukkit/plugin/SimplePluginManager.java
+++ b/src/main/java/org/bukkit/plugin/SimplePluginManager.java
@@ -462,7 +462,7 @@ 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 {
@@ -471,7 +471,7 @@ 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);
@@ -509,7 +509,7 @@ 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 {
@@ -579,6 +579,7 @@ 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.
@@ -587,23 +588,13 @@ 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.");
- }
- } else {
- if (!server.isPrimaryThread()) {
- throw new IllegalStateException(event.getEventName() + " cannot be triggered asynchronously from another thread.");
- }
+ // 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.");
}
- fireEvent(event);
- }
-
- 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 f188cd4f3..1941c9f49 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);
@@ -129,7 +129,7 @@ public class PluginManagerTest {
if (store.value == null) {
throw new IllegalStateException("No exception thrown");
}
- }
+ } */ // Paper
@Test
public void testRemovePermissionByNameLower() {
--
2.26.2