RE: copcall interpreter segfault possible?

[Thijs Schreijer <thijs@...>]

> -----Original Message-----
> From: lua-l-bounces@lists.lua.org [mailto:lua-l-bounces@lists.lua.org] On
> Behalf Of Fabio Mascarenhas
> Sent: maandag 10 juni 2013 18:06
> To: Lua mailing list
> Subject: Re: copcall interpreter segfault possible?
> 
> Thanks for the patch, Thijs, but I believe it is unrelated to the problem
> at hand. 

Yes I agree, it probably is unrelated. But doesn't hurt to try...

> I would bet on a misbehaving C library forgetting to do
> lua_checkstack and causing memory corruption in the heap.

Yes, I also suspect that Lua-EV is the culprit here.

> 
> Running the failing test under valgrind should be instructive, but I see
> someone closed the original issue, does that mean the cause was found?
> 

No it hasn't. A workaround was pulled in that no longer uses coxpcall with Lua-EV, which resolves the problem at hand, but not its root cause.
I have never use valgrind nor Lua-EV myself, but maybe Gerhard could give it a try?

Thijs

> 
> --
> Fabio Mascarenhas
> 
> On Mon, Jun 10, 2013 at 12:11 PM, Thijs Schreijer
> <thijs@thijsschreijer.nl> wrote:
> > -----Original Message-----
> > From: lua-l-bounces@lists.lua.org [mailto:lua-l-bounces@lists.lua.org]
> On
> > Behalf Of Gerhard Lipp
> > Sent: woensdag 5 juni 2013 15:15
> > To: lua-l@lists.lua.org
> > Subject: copcall interpreter segfault possible?
> >
> > Hi!
> >
> > As stated here https://github.com/Olivine-Labs/busted/issues/171, I am
> > observing a segmentation fault (Lua 5.1.5) when using copcall where
> > pcall should have been used.
> >
> > Unfortunately it is a rather complex situation but it is reproducible.
> > lua-ev is involved which itself makes some pcall through the lua API.
> > copcall and pcall may call each other in this scenario.
> >
> > Does this sound dangerous? Are there known scenarios where calling
> > copcall instead of pcall can crash the interpreter due to a badly
> > behaving C module?
> >
> > Regards,
> > Gerhard
> Not sure whether it fixes your problem. But I just submitted a PR [1] to
> fix an issue with coxpcall I ran into. You might want to give it a try.
> 
> Thijs
> 
> [1] https://github.com/keplerproject/coxpcall/pull/1
>