Re: [cdt-dev] Why doesn't DSF-GDB timeout when it submits query?

[Pawel Piech <pawel.piech@xxxxxxxxxxxxx>]

IMO, timeouts are a band-aid solution: do you really prefer a stuttering UI to a frozen one.  I have to admit though sometimes even band-aids are useful ;-)

Cheers,
Pawel

On 07/17/2012 10:22 AM, Andy Jin wrote:

Some users report the debug session hangs the IDE. The stack trace is copied below. At that stage, "gdb" hangs for some unknown reason (that will be looked at separately), but the stack trace shows DSF GDB is waiting for gdb infinitely and that hangs the main UI thread.

The org.eclipse.cdt.dsf.gdb.internal.ui.actions.GdbConnectCommand.canConnect() method sends the connect query using the org.eclipse.cdt.dsf.concurrent.Query.get() method. The "get()" method is blocked with no timeout. There is another "get(timeout, timeoutUnit)" method but it is not used.

In fact, I see almost all DSF-GDB classes use the "get()" method, e.g. GdbLaunchDelegate. In the case when gdb hangs, those methods will block. Is there any reason we don't use the "get(timeout, timoutUnit)" method?

Thanks,

Andy

"main" prio=6 tid=0x02269800 nid=0x1514 in Object.wait() [0x0018e000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x1ea4a7f0> (a
org.eclipse.cdt.dsf.concurrent.Query$QueryR
m)
        at java.lang.Object.wait(Object.java:485)
        at org.eclipse.cdt.dsf.concurrent.Query.get(Query.java:105)
        - locked <0x1ea4a7f0> (a org.eclipse.cdt.dsf.concurrent.Query$QueryRm)
        at
org.eclipse.cdt.dsf.gdb.internal.ui.actions.GdbConnectCommand.canConn
ect(GdbConnectCommand.java:100)
        at
org.eclipse.cdt.dsf.gdb.internal.ui.actions.ConnectActionDelegate.upd
ateEnablement(ConnectActionDelegate.java:65)
        at
org.eclipse.cdt.dsf.gdb.internal.ui.actions.ConnectActionDelegate.deb
ugContextChanged(ConnectActionDelegate.java:52)
        at
org.eclipse.debug.internal.ui.contexts.DebugWindowContextService$1.ru
n(DebugWindowContextService.java:194)
        at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
        at
org.eclipse.debug.internal.ui.contexts.DebugWindowContextService.noti
fy(DebugWindowContextService.java:192)
        at
org.eclipse.debug.internal.ui.contexts.DebugWindowContextService.noti
fy(DebugWindowContextService.java:181)
        at
org.eclipse.debug.internal.ui.contexts.DebugWindowContextService.debu
gContextChanged(DebugWindowContextService.java:390)
        at
org.eclipse.debug.ui.contexts.AbstractDebugContextProvider$1.run(Abst
ractDebugContextProvider.java:79)
        at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
        at
org.eclipse.debug.ui.contexts.AbstractDebugContextProvider.fire(Abstr
actDebugContextProvider.java:77)
        at
org.eclipse.debug.internal.ui.views.launch.LaunchView$ContextProvider
Proxy.debugContextChanged(LaunchView.java:477)
        at
org.eclipse.debug.ui.contexts.AbstractDebugContextProvider$1.run(Abst
ractDebugContextProvider.java:79)
        at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
        at
org.eclipse.debug.ui.contexts.AbstractDebugContextProvider.fire(Abstr
actDebugContextProvider.java:77)
        at
org.eclipse.debug.internal.ui.views.launch.LaunchView$TreeViewerConte
xtProvider.possibleChange(LaunchView.java:368)
        at
org.eclipse.debug.internal.ui.views.launch.LaunchView$TreeViewerConte
xtProvider$Visitor.visit(LaunchView.java:291)
        at org.eclipse.cdt.dsf.ui.viewmodel.VMDelta.doAccept(VMDelta.java:359)
        at org.eclipse.cdt.dsf.ui.viewmodel.VMDelta.doAccept(VMDelta.java:362)
        at org.eclipse.cdt.dsf.ui.viewmodel.VMDelta.accept(VMDelta.java:354)
        at
org.eclipse.debug.internal.ui.views.launch.LaunchView$TreeViewerConte
xtProvider.modelChanged(LaunchView.java:396)
        at
org.eclipse.debug.internal.ui.viewers.model.ModelContentProvider.doMo
delChanged(ModelContentProvider.java:1390)
        at
org.eclipse.debug.internal.ui.viewers.model.ModelContentProvider.mode
lChanged(ModelContentProvider.java:1364)
        at
org.eclipse.cdt.dsf.ui.viewmodel.DefaultVMModelProxyStrategy$1.run(De
faultVMModelProxyStrategy.java:144)
        at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
        at
org.eclipse.cdt.dsf.ui.viewmodel.DefaultVMModelProxyStrategy.fireMode
lChanged(DefaultVMModelProxyStrategy.java:148)
        at
org.eclipse.cdt.dsf.ui.viewmodel.update.AbstractCachingVMProvider$6.h
andleSuccess(AbstractCachingVMProvider.java:881)
        at
org.eclipse.cdt.dsf.concurrent.RequestMonitor.handleCompleted(Request
Monitor.java:353)
        at
org.eclipse.cdt.dsf.concurrent.RequestMonitor$2.run(RequestMonitor.ja
va:298)
        at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
        at
org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.ja
va:135)
        - locked <0x1ea4aa10> (a org.eclipse.swt.widgets.RunnableLock)
        at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
        at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
        at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2701)
        at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2665)
        at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
        at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
        at
org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.ja
va:332)
        at
org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.jav
a:668)
        at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
        at
org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEAppli
cation.java:123)
        at
org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandl
e.java:196)
        at
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runAppli
cation(EclipseAppLauncher.java:110)
        at
org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(Ec
lipseAppLauncher.java:79)
        at
org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.ja
va:344)
        at
org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.ja
va:179)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)        at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
        at org.eclipse.equinox.launcher.Main.run(Main.java:1410)

"VM Thread" prio=10 tid=0x0212f800 nid=0x1e3c runnable

"VM Periodic Task Thread" prio=10 tid=0x4cda8800 nid=0x6c8 waiting on condition

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