Debugging freeze due to RecursionLock critical:

> Hi all
>
> while at debugging, I sometimes get a debugger freeze (actually 7.6RC,
> but had the issue also on 7.3.1). The debugger window itself stands
> still, all fields and lists disabled, while the rest of VW still
> works. This is in our development image with tons of packages loaded,
> of course. A vanilla image had no problem in a short test (of course).
>
> Now I found that the debugger client waits on a semaphore that never
> gets signalled. This is during a recursion lock critical: section. a
> sample stack is attached below, might not be the right one for the
> debugger problem, but shows the issue.
>
> The point of interest is the #critical: method in RecursionLock:
>
>    | activeProcess |
>    activeProcess := Processor activeProcess.
>    ^activeProcess == owner
>        ifTrue: [aBlock value]
>        ifFalse:
>            [semaphore
>                critical:
>                    [owner := activeProcess.
>                    aBlock ensure: [owner := nil]]]
> In my case, where I could attach to such a hanging process, owner of
> the recursion lock was nil. But the test (owner == activeProcess)
> returns false in that case, halting the current process. But shouldn't
> the access be granted if owner is nil? The method #isLocked in
> RecursionLock also tests for nil as owner and answers false if owner
> is nil. So should the test rather be :
>
> (self isLocked not or: [owner == activeProcess])
>
> or maybe shorter
>
> (owner == nil or: [owner == activeProcess])
>
> I haven't yet found any reason why the vanilla behaves different, but
> this might come out as a tedious task.
>
> Has anyone any comments on this? Is this behavior right and the
> problem might be somewhere else?
>
> Thanks in advance
>
> Thomas
>
> ======================================================================================
>
>
> Name: BlockClosure>>ensure:  Priority: 50
> Semaphore>>waitIfCurtailedSignal
> Semaphore>>critical:
> RecursionLock>>critical:
> ProcessEnvironment>>at:ifAbsent:
> Process>>exceptionHandlers
> Process>>popExceptionHandler
> optimized [] in BlockClosure>>on:do:
> BlockClosure>>valueAsUnwindBlockFrom:
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> MethodContext(Context)>>doPrimitive:receiver:numArgs:boundByMethod:
> MethodContext(Context)>>tryPrimitive:receiver:numArgs:boundByMethod:
> MethodContext(Context)>>runMethod:numArgs:contextClass:
> [] in MethodContext(Context)>>send:receiver:class:super:numArgs:
> MethodContext(Context)>>findMethod:class:ifFound:
> MethodContext(Context)>>send:receiver:class:super:numArgs:
> MethodContext(Context)>>send:numArgs:
> MethodContext(Context)>>sendNonImmediate:numArgs:
> optimized [] in InstructionStream
> class>>initializeXMisc:numberOfExtensions:combinationRule:
> MethodContext(InstructionStream)>>interpretNextInstructionFor:
> optimized [] in Context>>safelyInterpretNextInstructionFor:
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> MethodContext(Context)>>safelyInterpretNextInstructionFor:
> optimized [] in Context>>step
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> MethodContext(Context)>>step
> optimized [] in Context>>sendIntoBlockStartingWithCallee:
> BlockClosure>>ensure:
> MethodContext(Context)>>sendIntoBlockStartingWithCallee:
> BlockContext>>stepToCtxtWithSameParentAs:
> optimized [] in DebuggerService>>privateStepIntoBlock
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> DebuggerService>>privateStepIntoBlock
> optimized [] in DebuggerService>>basicStepIntoBlock
> optimized [] in [] in [] in DebuggerService>>performDebugOperation:
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> optimized [] in [] in DebuggerService>>performDebugOperation:
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> optimized [] in DebuggerService>>performDebugOperation:
> optimized [] in [] in ProcessHandle>>performDebugOperation:
> BlockClosure>>ensure:
> BlockClosure>>on:do:
> optimized [] in ProcessHandle>>performDebugOperation:
>
>
>
> "self isLocked not"
>