[Vm-dev] FW: [Pharo-project] Debugging Cog crash

Eliot Miranda eliot.miranda at gmail.com
Sun Apr 10 13:46:39 UTC 2011


Hi Bill,

On Fri, Apr 8, 2011 at 4:58 AM, Schwab,Wilhelm K <bschwab at anest.ufl.edu>wrote:

>
> Gratuitous default recipient...
>
> If there is a verbose dump option or other diagnostic efforts that will
> help, I will do my best to run them and report the results.  I am fairly
> certain the vm is 'Croquet Closure Cog VM [CoInterpreter VMMaker-oscog.54]'
> (can verify later today), but this happened with an earlier Cog one-click
> too.  There is something about the machine (UUID again?) that is different.
>  I do not have root access to it, but I can get to a terminal.  Ubuntu
> 10.10.
>

you could use the send tracing that's in the Cog VMs to see if it gets as
far as running Smalltalk code, and if so, the last thing it manages to
execute:

$ coglinux/squeak -sendtrace=9 all/Squeak/Squeak4.2/trunk4.2.image
SmalltalkImage class>current
[] in SmalltalkImage>send:toClassesNamedIn:with:
[] in SmalltalkImage>send:toClassesNamedIn:with:
SmalltalkImage>at:ifAbsent:
SystemDictionary(Dictionary)>at:ifAbsent:
SystemDictionary>scanFor:
ByteSymbol(String)>hash
ByteString class(ProtoObject)>identityHash
ByteSymbol class>stringHash:initialHash:
ByteString class>stringHash:initialHash:
Array(Object)>at:
Association(LookupKey)>key
Array(Object)>at:
Association(LookupKey)>key
Array(ArrayedCollection)>size
SmallInteger>\\

Alas there is the possibility of heisenbugs here since adding tracing
changes the code that the VM generates and hence changes the frequencies of
code compactions.  But it may be of use.  Also, sorry about the
-sendtrace=9.  It should of course default to the right magic value, so one
would need only to say "coglinux/squeak -sendtrace
all/Squeak/Squeak4.2/trunk4.2.image".  I'll add this to the list...


>
> ________________________________________
> From: Schwab,Wilhelm K
> Sent: Friday, April 08, 2011 7:44 AM
> To: Mariano Martinez Peck
> Subject: RE: [Pharo-project] Debugging Cog crash
>
> Mariano,
>
> I first identified this problem/opportunity a while ago.  At the time,
> there was no log - the vm just died.  I can sniff around again as there
> might be one this time.  My question at the time was whether there was
> something that I could enable to perhaps get more info.
>
> The output from the vm is, and I quote<g> "Segmentation fault".  There is
> no other output.  Perhaps it does not get far enough to have a call stack??
>
> Bill
>
>
>
> ________________________________________
> From: Mariano Martinez Peck [marianopeck at gmail.com]
> Sent: Friday, April 08, 2011 3:42 AM
> To: Squeak Development Discussion Virtual Machine; Pharo Development
> Cc: Schwab,Wilhelm K
> Subject: Re: [Pharo-project] Debugging Cog crash
>
> also...shouldn't be a crash/dump file somewhere?
>
> can you write the output of the console where you invoke the VM into a file
> ?   (using > to redirect)
>
> Cheers
>
> Mariano
>
> On Thu, Apr 7, 2011 at 11:10 PM, Schwab,Wilhelm K <bschwab at anest.ufl.edu
> <mailto:bschwab at anest.ufl.edu>> wrote:
> Hello all,
>
> I have an account on an Ubuntu terminal server (at least I think that's
> what it would be called) running 10.10.  The Cog one-click image crashes
> with "Segmentation fault" (if run from a terminal); the legacy VM seems to
> run the image nicely on the box.  Any ideas?  I will happily collect any
> facts that will be of help, but I need some
> direction.
>
> Bill
>
>
>
>
>
>
> --
> Mariano
> http://marianopeck.wordpress.com
>
>
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