[Vm-dev] CogVM crash when printing related to #cannotInterpret:

Mariano Martinez Peck marianopeck at gmail.com
Mon Oct 3 09:35:53 UTC 2011

Hi Eliot. I am testing your very last VM r2496, CogMT in Mac OS 10.6.8. I am
using the trick of #cannotInterpret: and I discover a problem with it.
Basically, it is when doing something like this:

MyProxy >> cannotInterpret: aMessage

Error signal: 'ups...'.

In this case, the debugger comes in but after one or 2 times I press in the
debugger line of #cannotInterpret: (to debug it), it crashes. As far as I
could see with gdb, the problem is in MethodContext >> #printDetails:
If I comment the contents of such method, I have no crash at all. I think
that in this scenario where I throw an arror inside #cannotInterpret can
reach a situation where you don't have temps or values or receiver or
something and that's why it crash.
Furthermore, previous VM version, do NOT have this problem.

I will try to dig a little more, but if you give me a hint, I appreciate it.

Here is the bt and the stack:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_PROTECTION_FAILURE at address: 0x00000026
0x000d8356 in methodHasCogMethod ()
(gdb) bt
#0  0x000d8356 in methodHasCogMethod ()
#1  0x000c7899 in cogPICSelectornumArgsCase0MethodCase1MethodtagisMNUCase ()
#2  0x000d6eea in ceSICMiss ()
#3  0x13ffc35c in ?? ()
#4  0x00107a05 in threadSchedulingLoop ()
#5  0x00108c38 in initStackPagesAndInterpret ()
#6  0x0005d964 in EventLoopEventHandler ()
#7  0x98c66c2f in DispatchEventToHandlers ()
#8  0x98c65ef6 in SendEventToEventTargetInternal ()
#9  0x98c65d55 in SendEventToEventTargetWithOptions ()
#10 0x98c9aa24 in ToolboxEventDispatcherHandler ()
#11 0x98c67080 in DispatchEventToHandlers ()
#12 0x98c65ef6 in SendEventToEventTargetInternal ()
#13 0x98c887f3 in SendEventToEventTarget ()
#14 0x98e11c17 in ToolboxEventDispatcher ()
#15 0x98e11d4f in RunApplicationEventLoop ()
#16 0x0005d18a in RunApplicationEventLoopWithSqueak ()
#17 0x0006ebf7 in main ()

(gdb) call (int) printAllStacks()
Process 0x171793f8 priority 40
0xbff69d64 M [] in MethodContext>printDetails: 387422092: a(n) MethodContext
0xbff69d80 M BlockClosure>on:do: 388720820: a(n) BlockClosure
0xbff69da0 M BlockClosure>ifError: 388720820: a(n) BlockClosure
0xbff69dc8 M MethodContext>printDetails: 387422092: a(n) MethodContext
0xbff69df0 M MethodContext(ContextPart)>errorReportOn: 387418688: a(n)
0xbff69e1c I [] in SmalltalkImage>logError:inContext: 340435416: a(n)
0xbff69e48 I [] in SmalltalkImage>logDuring: 340435416: a(n) SmalltalkImage
0xbff69e68 M BlockClosure>ensure: 388309644: a(n) BlockClosure
0xbff69e90 I SmalltalkImage>logDuring: 340435416: a(n) SmalltalkImage
0xbff69eb4 I SmalltalkImage>logError:inContext: 340435416: a(n)
0xbff69ef0 M [] in
MorphicUIManager>openDebuggerOn:context:label:contents:fullView: 338485116:
a(n) MorphicUIManager
0xbff69f0c M BlockClosure>on:do: 387421948: a(n) BlockClosure
0xbff69f44 M [] in
MorphicUIManager>openDebuggerOn:context:label:contents:fullView: 338485116:
a(n) MorphicUIManager
0xbff69f64 M WorldState>runStepMethodsIn: 338433128: a(n) WorldState
0xbff69f80 M PasteUpMorph>runStepMethods 338272244: a(n) PasteUpMorph
0xbff69f98 M WorldState>doOneCycleNowFor: 338433128: a(n) WorldState
0xbff69fb4 M WorldState>doOneCycleFor: 338433128: a(n) WorldState
0xbff69fd0 M PasteUpMorph>doOneCycle 338272244: a(n) PasteUpMorph
0xbff69ff0 I [] in Project class>spawnNewProcess 338672796: a(n) Project
0xbff6a010 I [] in BlockClosure>newProcess 387420956: a(n) BlockClosure

Process 0x1711e7fc priority 50
0xbff5ffd0 M WeakArray class>finalizationProcess 337425280: a(n) WeakArray
0xbff5fff0 I [] in WeakArray class>restartFinalizationProcess 337425280:
a(n) WeakArray class
0xbff60010 I [] in BlockClosure>newProcess 387049248: a(n) BlockClosure

Process 0x14a27698 priority 80
0xbff60ff0 M Delay class>handleTimerEvent 337430620: a(n) Delay class
0xbff61010 I Delay class>? 337430620: a(n) Delay class
346191180 s [] in Delay class>?
346191416 s [] in BlockClosure>?

Process 0x15d37dd0 priority 40
366182080 s [] in SHTextStylerST80(SHTextStyler)>styleInBackgroundProcess:
366181744 s [] in BlockClosure>newProcess

Process 0x166a5108 priority 60
0xbff61fd0 I SmalltalkImage>lowSpaceWatcher 340435416: a(n) SmalltalkImage
0xbff61ff0 I [] in SmalltalkImage>installLowSpaceWatcher 340435416: a(n)
0xbff62010 I [] in BlockClosure>newProcess 376066092: a(n) BlockClosure

Process 0x1711c3d8 priority 60
0xbff64f50 M [] in Delay>wait 387040292: a(n) Delay
0xbff64f70 M BlockClosure>ifCurtailed: 387932080: a(n) BlockClosure
0xbff64f8c M Delay>wait 387040292: a(n) Delay
0xbff64fa4 M InputEventPollingFetcher>waitForInput 337872084: a(n)
0xbff64fd0 I InputEventPollingFetcher(InputEventFetcher)>eventLoop
337872084: a(n) InputEventPollingFetcher
0xbff64ff0 I [] in
InputEventPollingFetcher(InputEventFetcher)>installEventLoop 337872084: a(n)
0xbff65010 I [] in BlockClosure>newProcess 387039996: a(n) BlockClosure

processes at priority 10
Process 0x166a52d4 priority 10
0xbff63fd0 M ProcessorScheduler class>idleProcess 337424860: a(n)
ProcessorScheduler class
0xbff63ff0 I [] in ProcessorScheduler class>startUp 337424860: a(n)
ProcessorScheduler class
0xbff64010 I [] in BlockClosure>newProcess 376066552: a(n) BlockClosure
$1 = 0

Thanks in advance,

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