Re: [cdt-dev] Disassembly view throws NPE when debugging with CDI

[Pawel Piech <pawel.piech@xxxxxxxxxxxxx>]

On 06/17/2010 09:17 AM, John Cortell wrote:
> Andy,
>
> Something strange is going on. Notice that the code to get the top 
> stack frame only executes if the new context is a stack frame. So, how 
> is it that we are being given a stack frame as the new context but 
> that frame's thread isn't suspended?
When stepping, a thread's frames are shown in DV but technically the 
thread is running.
Cheers,
Pawel
> On the surface, it looks like a bug somewhere else--a race condition 
> or some incoherent state. If you could figure out a way to rig the CDT 
> code to duplicate what's happening for you, and provide that as a 
> patch, that would allow us to reproduce it and investigate further.
>
> John
>
> At 10:54 AM 6/17/2010, Andy Jin wrote:
> > When debugging a program with a large share library linked over a remote
> > target, the program takes some time to be load the share library. During
> > this loading period if I have the Disassembly view opened it will throw
> > NPE with below trace:
> >
> > java.lang.NullPointerException
> > at
> > org.eclipse.cdt.debug.internal.ui.disassembly.dsf.DisassemblyBackendCdi.setDebugContext(DisassemblyBackendCdi.java:132) 
> >
> > at
> > org.eclipse.cdt.dsf.debug.internal.ui.disassembly.DisassemblyPart.updateDebugContext(DisassemblyPart.java:1798) 
> >
> > at org.eclipse.cdt.dsf.debug.internal.ui.disassembly.DisassemblyView
> > $1.selectionChanged(DisassemblyView.java:66)
> > at org.eclipse.ui.internal.AbstractPartSelectionTracker
> > $1.run(AbstractPartSelectionTracker.java:119)
> > at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
> > at org.eclipse.core.runtime.Platform.run(Platform.java:888)
> > at
> > org.eclipse.ui.internal.AbstractPartSelectionTracker.fireSelection(AbstractPartSelectionTracker.java:117) 
> >
> > at org.eclipse.ui.internal.PagePartSelectionTracker
> > $1.selectionChanged(PagePartSelectionTracker.java:49)
> > ......................................
> >
> > Looking at
> > org.eclipse.cdt.debug.internal.ui.disassembly.dsf.DisassemblyBackendCdi.setDebugContext(DisassemblyBackendCdi.java:132), 
> > it does a "fTargetContext.getTopStackFrame()". This function can 
> > return Null if the thread is not in suspended mode thus the stack 
> > frame is an empty list.
> >
> > In our case the program is in the process of loading the share library
> > so its thread is not suspended.
> >
> > It's pretty re-producible with CDI. I haven't seen this problem with
> > DSF.
> >
> > Is it simply a miss to check for Null condition or is it something
> > deeper in the code?
> >
> > Thanks,
> > Andy
> > _______________________________________________
> > cdt-dev mailing list
> > cdt-dev@xxxxxxxxxxx
> > https://dev.eclipse.org/mailman/listinfo/cdt-dev
>
>
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