Details
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Bug
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Resolution: Fixed
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Blocker
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11.9
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Unit
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Unknown
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N/A
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N/A
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Description
LogbackEventGenerator is synchronized because it extends AppenderBase which has a synchronized doAppend method. This means that only one thread can generate log events at the same time (which is already not great for performance, not needed and was actually not expected).
Combined with AbstractFileLoggerTail (which needs locking between read and write operations on the log tail) you can end up with a dead lock when a read on another thread fails (and log the error) while a write is waiting.
Here is an example:
"***some thread storing a new log***": at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.writeLog(AbstractFileLoggerTail.java:270) - waiting to lock <0x00000000d3537ff8> (a org.xwiki.logging.internal.tail.XStreamFileLoggerTail) at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.log(AbstractFileLoggerTail.java:261) at org.xwiki.logging.event.LoggerListener.onEvent(LoggerListener.java:70) at org.xwiki.observation.WrappedThreadEventListener.onEventInternal(WrappedThreadEventListener.java:77) at org.xwiki.observation.AbstractThreadEventListener.onEvent(AbstractThreadEventListener.java:57) at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:320) at org.xwiki.observation.internal.DefaultObservationManager.notify(DefaultObservationManager.java:285) at org.xwiki.logging.logback.internal.LogbackEventGenerator.append(LogbackEventGenerator.java:149) at org.xwiki.logging.logback.internal.LogbackEventGenerator.append(LogbackEventGenerator.java:64) at ch.qos.logback.core.AppenderBase.doAppend(AppenderBase.java:82) - locked <0x00000000b88542a8> (a org.xwiki.logging.logback.internal.LogbackEventGenerator) at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:51) at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:270) at ch.qos.logback.classic.Logger.callAppenders(Logger.java:257) at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:421) at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:383) at ch.qos.logback.classic.Logger.warn(Logger.java:716) at org.xwiki.filter.xar.internal.input.WikiReader.read(WikiReader.java:142) at org.xwiki.filter.xar.internal.input.WikiReader.read(WikiReader.java:95) at org.xwiki.filter.xar.internal.input.XARInputFilterStream.readXAR(XARInputFilterStream.java:108) at org.xwiki.filter.xar.internal.input.XARInputFilterStream.read(XARInputFilterStream.java:95) at org.xwiki.filter.xar.internal.input.XARInputFilterStream.read(XARInputFilterStream.java:47) at org.xwiki.filter.input.AbstractBeanInputFilterStream.read(AbstractBeanInputFilterStream.java:79) at org.xwiki.filter.internal.job.FilterStreamConverterJob.runInternal(FilterStreamConverterJob.java:97) at org.xwiki.job.AbstractJob.runInContext(AbstractJob.java:240) at org.xwiki.job.AbstractJob.run(AbstractJob.java:217) at org.xwiki.filter.script.internal.ScriptFilterStreamConverterJob.run(ScriptFilterStreamConverterJob.java:75) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) "***some thread reading the stored log ***": at ch.qos.logback.core.AppenderBase.doAppend(AppenderBase.java:63) - waiting to lock <0x00000000b88542a8> (a org.xwiki.logging.logback.internal.LogbackEventGenerator) at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:51) at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:270) at ch.qos.logback.classic.Logger.callAppenders(Logger.java:257) at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:421) at ch.qos.logback.classic.Logger.filterAndLog_2(Logger.java:414) at ch.qos.logback.classic.Logger.error(Logger.java:530) at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.getLogEvent(AbstractFileLoggerTail.java:336) at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.getLogEvent(AbstractFileLoggerTail.java:312) at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.getLogEvents(AbstractFileLoggerTail.java:466) at org.xwiki.logging.internal.tail.AbstractFileLoggerTail.getLogEvents(AbstractFileLoggerTail.java:448) - locked <0x00000000d3537ff8> (a org.xwiki.logging.internal.tail.XStreamFileLoggerTail) at org.xwiki.logging.tail.LogTail.getLogEvents(LogTail.java:54) at sun.reflect.GeneratedMethodAccessor1192.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280) at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:567) at org.apache.velocity.runtime.directive.Foreach.render(Foreach.java:318) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222) at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358) at org.xwiki.rendering.internal.macro.velocity.VelocityMacro.evaluateString(VelocityMacro.java:131) at org.xwiki.rendering.internal.macro.velocity.VelocityMacro.evaluateString(VelocityMacro.java:52) at org.xwiki.rendering.macro.script.AbstractScriptMacro.evaluateBlock(AbstractScriptMacro.java:286) at org.xwiki.rendering.macro.script.AbstractScriptMacro.execute(AbstractScriptMacro.java:182) at org.xwiki.rendering.macro.script.AbstractScriptMacro.execute(AbstractScriptMacro.java:58) at org.xwiki.rendering.internal.transformation.macro.MacroTransformation.transform(MacroTransformation.java:297) at org.xwiki.rendering.internal.transformation.DefaultRenderingContext.transformInContext(DefaultRenderingContext.java:183) at org.xwiki.rendering.internal.transformation.DefaultTransformationManager.performTransformations(DefaultTransformationManager.java:101) at org.xwiki.display.internal.DocumentContentAsyncExecutor.executeInCurrentExecutionContext(DocumentContentAsyncExecutor.java:348) at org.xwiki.display.internal.DocumentContentAsyncExecutor.execute(DocumentContentAsyncExecutor.java:221) at org.xwiki.display.internal.DocumentContentAsyncRenderer.execute(DocumentContentAsyncRenderer.java:107) at org.xwiki.rendering.async.internal.block.AbstractBlockAsyncRenderer.render(AbstractBlockAsyncRenderer.java:157) at org.xwiki.rendering.async.internal.block.AbstractBlockAsyncRenderer.render(AbstractBlockAsyncRenderer.java:54) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.syncRender(DefaultAsyncRendererExecutor.java:270) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.render(DefaultAsyncRendererExecutor.java:247) at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.execute(DefaultBlockAsyncRendererExecutor.java:125) at org.xwiki.display.internal.DocumentContentDisplayer.display(DocumentContentDisplayer.java:67) at org.xwiki.display.internal.DocumentContentDisplayer.display(DocumentContentDisplayer.java:43) at org.xwiki.display.internal.DefaultDocumentDisplayer.display(DefaultDocumentDisplayer.java:96) at org.xwiki.display.internal.DefaultDocumentDisplayer.display(DefaultDocumentDisplayer.java:39) at org.xwiki.sheet.internal.SheetDocumentDisplayer.display(SheetDocumentDisplayer.java:123) at org.xwiki.sheet.internal.SheetDocumentDisplayer.display(SheetDocumentDisplayer.java:52) at org.xwiki.display.internal.ConfiguredDocumentDisplayer.display(ConfiguredDocumentDisplayer.java:68) at org.xwiki.display.internal.ConfiguredDocumentDisplayer.display(ConfiguredDocumentDisplayer.java:42) at com.xpn.xwiki.doc.XWikiDocument.display(XWikiDocument.java:1210) at com.xpn.xwiki.doc.XWikiDocument.getRenderedContent(XWikiDocument.java:1351) at com.xpn.xwiki.doc.XWikiDocument.displayDocument(XWikiDocument.java:1300) at com.xpn.xwiki.api.Document.displayDocument(Document.java:762) at sun.reflect.GeneratedMethodAccessor566.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280) at org.apache.velocity.runtime.parser.node.ASTReference.value(ASTReference.java:567) at org.apache.velocity.runtime.parser.node.ASTExpression.value(ASTExpression.java:71) at org.apache.velocity.runtime.parser.node.ASTSetDirective.render(ASTSetDirective.java:142) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.parser.node.ASTIfStatement.render(ASTIfStatement.java:87) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.xwiki.velocity.introspection.TryCatchDirective.render(TryCatchDirective.java:87) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222) at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358) at com.xpn.xwiki.internal.template.VelocityTemplateEvaluator.evaluateContent(VelocityTemplateEvaluator.java:95) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.evaluateContent(TemplateAsyncRenderer.java:217) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.renderVelocity(TemplateAsyncRenderer.java:180) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:137) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:53) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.lambda$syncRender$0(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor$$Lambda$383/943990550.call(Unknown Source) at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.syncRender(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.render(DefaultAsyncRendererExecutor.java:247) at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.render(DefaultBlockAsyncRendererExecutor.java:154) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:772) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:745) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:725) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:711) at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2490) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:2468) at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:992) at sun.reflect.GeneratedMethodAccessor340.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222) at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358) at com.xpn.xwiki.internal.template.VelocityTemplateEvaluator.evaluateContent(VelocityTemplateEvaluator.java:95) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.evaluateContent(TemplateAsyncRenderer.java:217) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.renderVelocity(TemplateAsyncRenderer.java:180) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:137) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:53) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.lambda$syncRender$0(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor$$Lambda$383/943990550.call(Unknown Source) at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.syncRender(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.render(DefaultAsyncRendererExecutor.java:247) at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.render(DefaultBlockAsyncRendererExecutor.java:154) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:772) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:745) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:725) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:711) at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2490) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:2468) at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:992) at sun.reflect.GeneratedMethodAccessor340.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222) at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358) at com.xpn.xwiki.internal.template.VelocityTemplateEvaluator.evaluateContent(VelocityTemplateEvaluator.java:95) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.evaluateContent(TemplateAsyncRenderer.java:217) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.renderVelocity(TemplateAsyncRenderer.java:180) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:137) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:53) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.lambda$syncRender$0(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor$$Lambda$383/943990550.call(Unknown Source) at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.syncRender(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.render(DefaultAsyncRendererExecutor.java:247) at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.render(DefaultBlockAsyncRendererExecutor.java:154) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:772) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:745) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:725) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:711) at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2490) at com.xpn.xwiki.XWiki.parseTemplate(XWiki.java:2468) at com.xpn.xwiki.api.XWiki.parseTemplate(XWiki.java:992) at sun.reflect.GeneratedMethodAccessor340.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:395) at org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:384) at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:173) at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:280) at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:369) at org.apache.velocity.runtime.parser.node.ASTBlock.render(ASTBlock.java:72) at org.apache.velocity.runtime.directive.VelocimacroProxy.render(VelocimacroProxy.java:216) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:311) at org.apache.velocity.runtime.directive.RuntimeMacro.render(RuntimeMacro.java:230) at org.apache.velocity.runtime.parser.node.ASTDirective.render(ASTDirective.java:207) at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:342) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluateInternal(DefaultVelocityEngine.java:259) at org.xwiki.velocity.internal.DefaultVelocityEngine.evaluate(DefaultVelocityEngine.java:222) at com.xpn.xwiki.render.DefaultVelocityManager.evaluate(DefaultVelocityManager.java:358) at com.xpn.xwiki.internal.template.VelocityTemplateEvaluator.evaluateContent(VelocityTemplateEvaluator.java:95) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.evaluateContent(TemplateAsyncRenderer.java:217) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.renderVelocity(TemplateAsyncRenderer.java:180) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:137) at com.xpn.xwiki.internal.template.TemplateAsyncRenderer.render(TemplateAsyncRenderer.java:53) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.lambda$syncRender$0(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor$$Lambda$383/943990550.call(Unknown Source) at com.xpn.xwiki.internal.security.authorization.DefaultAuthorExecutor.call(DefaultAuthorExecutor.java:98) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.syncRender(DefaultAsyncRendererExecutor.java:264) at org.xwiki.rendering.async.internal.DefaultAsyncRendererExecutor.render(DefaultAsyncRendererExecutor.java:247) at org.xwiki.rendering.async.internal.block.DefaultBlockAsyncRendererExecutor.render(DefaultBlockAsyncRendererExecutor.java:154) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:772) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:745) at com.xpn.xwiki.internal.template.InternalTemplateManager.renderFromSkin(InternalTemplateManager.java:725) at com.xpn.xwiki.internal.template.InternalTemplateManager.render(InternalTemplateManager.java:711) at com.xpn.xwiki.internal.template.DefaultTemplateManager.render(DefaultTemplateManager.java:78) at com.xpn.xwiki.XWiki.evaluateTemplate(XWiki.java:2490) at com.xpn.xwiki.web.Utils.parseTemplate(Utils.java:179) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:516) at com.xpn.xwiki.web.XWikiAction.execute(XWikiAction.java:218) at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425) at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228) at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913) at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449) at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at com.xpn.xwiki.web.ActionFilter.doFilter(ActionFilter.java:112) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:109) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:132) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:679) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) - locked <0x00000000d4e95158> (a org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Found 1 deadlock.
According to LogBack documentation the root problem is that LogbackEventGenerator should have extended UnsynchronizedAppenderBase and not AppenderBase.