[Vm-dev] Segfaulting cog vm on FreeBSD

[David T. Lewis]

Look for the method that calls #primitiveMakeUUID. Probably that will be
UUID>>primMakeUUID. Then comment out this line:

	"<primitive: 'primitiveMakeUUID' module: 'UUIDPlugin'>"

The will prevent calls to the plugin, effectively disabling it.

When you are done testing, revert your #primMakeUUID method back to the
way it was before.

Dave


>
> OK - how to  "temporarily remove UUIDPlugin"? Thanks, pf
>
>
>>
>> That's all fine. What I was trying to hint that maybe the UUID plugin is
>> broken (it is definitely not generating UUIDs, since the fallback code
>> is executed) and it messes up the object memory, which results in a
>> crash in the GC. That's why I asked if it crashes with the plugin
>> removed.
>>
>> Levente
>>
>> On Mon, 18 Jul 2016, Petr Fischer wrote:
>>
>> >
>> > I am generating/instantiating thousand of objects (my simple data
>> classes), and then persisting this medium sized object graph with Fuel
>> to file.
>> > While I am preparing object graph, UUID generator is used for
>> generating random IDs and is called thousands times.
>> > Final crash is in "scavengeReferentsOf" (via gdb) - probably Garbage
>> Collector.
>> >
>> > pf
>> >
>> >>
>> >> The image was generating an UUID when the crash happened. But
>> primMakeUUID
>> >> seem to had failed and the crash happened in the fallback code.
>> >> Does the VM crash if you temporarily remove UUIDPlugin?
>> >>
>> >> Levente
>> >>
>> >> On Sun, 17 Jul 2016, Petr Fischer wrote:
>> >>
>> >>>
>> >>> Hello! Moving discussion about %subj% from pharo-dev list.
>> >>> My problem on FreeBSD:
>> >>>
>> >>> There is a linux compatibility layer on FreeBSD (even 64bits on
>> 11-CURRENT), so there is no theoretical problem running pharo linux
>> vms.
>> >>> But: complete linux libraries comming from centos 6.7, where is
>> glibc older than 2.15 - so, no luck with actual default pharo vm
>> from pharo.org.
>> >>> So I compiled my own pharo-vm on CentOS 6.7 with old glibc,
>> everything is OK on Linux CentOS box, but on the FreeBSD side, vm is
>> segfaulting (my own compiled "stack" vm is more stable, but
>> segfaulting too).
>> >>> I compiled from pharo-vm git:
>> >>> https://github.com/pharo-project/pharo-vm
>> >>>
>> >>> I am building "PharoVMSpur32Builder buildUnix32" (there is some old
>> "PharoVMBuilder buildFreeBSD", but probably unmaintained).
>> >>>
>> >>> Why I can't compile directly on the FreeBSD without Linux
>> compatibility layer? Because there is a step, when I need to Load
>> VMMaker into functional stable image - when I use my compiled vm, of
>> course, segfaulting while loading VMMaker... Therefore I am going
>> via Linux comp. layer. Native port of vm for FreeBSD will be the
>> next step.
>> >>>
>> >>> Ok, ok, next steps... I compiled my own "debug vm" (cog, spur, again
>> on CentOS 6.7) and here is some outputs from my gdb session (I am
>> definitely not Core C hacker):
>> >>>
>> >>> Crashing code snippet - function is "scavengeReferentsOf" and
>> crashing line is 110:
>> >>> http://pastebin.com/yK7YJig2
>> >>>
>> >>> Backtrace:
>> >>> http://pastebin.com/jMgzE9G0
>> >>>
>> >>> printAllStacks:
>> >>> http://pastebin.com/VP1nwrsC
>> >>>
>> >>> Now I am at end with my knowledge (vm internals) - but I can add
>> some printf/log outputs into generated C files, recompile and
>> retest.
>> >>>
>> >>> Any ideas? Thanks very much. pf
>> >>>
>> >
>