AW: [Caml-list] Segmentation fault right after caml_alloc_custom

[Gerd Stolpmann <info@gerd-stolpmann.de>]

You did not send code, so we can only speculate. A reason for this  
behavior could be that a value is not registered as local root, so the  
GC thinks it is unused.

That you see the problem only on some platforms can be explained by the  
different implementations of malloc, and how quickly freed memory is  
really deallocated (i.e. given back to the kernel). I wouldn't give  
much on this observation.

Gerd

Am 01.08.2012 22:05:19 schrieb(en) Lin Hong:
> Hi all,
> 
> we have a weird problem here. In a c file, right after one call of  
> 'caml_alloc_custom', some old information we have in memory is gone,  
> then we have the segmentation fault because the code try to access  
> those informations later.
> 
>  turn on debug message with OCAMLRUNPARAM, get this right before it  
> crash.
> 
> ......
> $Starting new major GC cycle
> Marking 9223372036854775807 words
> Subphase = 10
> Sweeping 9223372036854775807 words
> Compacting heap...
> Shrinking heap to 37696k bytes
> Shrinking heap to 36704k bytes
> Shrinking heap to 35712k bytes
> Shrinking heap to 34720k bytes
> Shrinking heap to 33728k bytes
> Shrinking heap to 32736k bytes
> Shrinking heap to 31744k bytes
> Shrinking heap to 30752k bytes
> done.
> 
> is it possible that the ocaml garbage collection free memory that is  
> still in use?
> 
> the data cause this is kind of big, it doesn't happen right away,and  
> it doesn't happen on every machine (linux with ocaml4 is fine,  
> ocaml3.xx is not. mac with ocaml4 still shows the problem though).
> 
> any suggestion is appreciated.
> 
> 
> Thanks,
> Lin
> 
> 
> =======================
> American Museum of Natural History
> POY website :
> https://code.google.com/p/poy/
> http://research.amnh.org/scicomp/scripts/download.php
> 
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa-roc.inria.fr/wws/info/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
> 
> 

-- 
------------------------------------------------------------
Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de
Creator of GODI and camlcity.org.
Contact details:        http://www.camlcity.org/contact.html
Company homepage:       http://www.gerd-stolpmann.de
------------------------------------------------------------