[Vm-dev] Segfaults from #copyStack
eliot.miranda at gmail.com
Sun Feb 25 00:03:50 UTC 2018
On Sat, Feb 24, 2018 at 2:57 PM, Max Leske <maxleske at gmail.com> wrote:
> Thanks Eliot.
> On 24 February 2018 at 22:15:21, vm-dev-request at lists.squeakfoundation.org
> (vm-dev-request at lists.squeakfoundation.org) wrote:
> Hi Max,
> On Sat, Feb 24, 2018 at 1:07 PM
> <http://airmail.calendar/2018-02-24%2013:07:00%20CET>, Max Leske <
> maxleske at gmail.com> wrote:
> > Hi,
> > I'm seeing many segfaults (around 20 to 30% of the time) when running
> > builds on Linux. Everytime I see it it's caused by #copyStack (e.g.
> > https://travis-ci.org/theseion/Fuel/jobs/345741310). AFAICT it happens
> > more often (exclusively?) on 32 bit with Pharo 7 (latest VM + latest
> Try and construct a test case that crashes without user interaction. i.e.
> something that starts up with a known image, supplying a script to load via
> Fuel. Once this crashes reliably debugging is easy. Otherwise its very
> hard. As soon as you have the crashing test case let me know and I'll take
> a look. Ideally it would run on Mac OS X.
> I've tried for the last two hours to come up with a reliable way of
> triggering the segfault but haven't had any luck. I can only reproduce it
> on Linux, not macOS and I've only been able to force the segfault with
> using smalltalkCI:
> git clone https://github.com/hpi-swa/smalltalkCI.git && git clone
> https://github.com/theseion/Fuel.git && smalltalkCI/run.sh -s Pharo-alpha
> I used Ubuntu 17.04 (32-bit), TravisCI uses 14.04.5 (64-bit).
> Maybe there's a way I can extract some information you can use? And then
> I'll just play mole whacking until I trigger it... :)
There should at least be a crash.dmp file that should contain a reasonably
informative stack trace and register set. What does that show you? When
you combine the crash.mp output with a gdb session you can find the
offending instruction and relate that to the register set in crash.mp to
find out the instruction that caused the crash. Tracing back form that
isn't necessarily trivial but at least one has started :-)
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