[Scilab-users] ?==?utf-8?q? scilab 6.1 crashes when trying to load big matfile (loadmatfile)

[Antoine Monmayrant]

Le Vendredi, Juin 19, 2020 15:59 CEST, Rafael Guerra <jrafaelbguerra at hotmail.com> a écrit: 
 
> Script runs fine on Win10, Scilab 6.1, 64 GB RAM.
> But btw, the file a28.mat seems to have only 342MB.

I suspect that it does work fine with 64GB of ram: that's how I managed to work around my initial problem.
This script should be adapted to your available ram: you should try to increase n.
But in your case, I think you have enough ram to reach scilab maximum variable size (is it something like 2^31-1 maximum elements?) before triggering this bug.
Ideally, this should be tested on a ram-limited hardware (~8GB).
The issue is that there might be some malloc() somewhere that fails, while the code tries to use the memory without checking whether the malloc() was successful or not.
If you have gazillion's of GB of available ram, you never face this problem.

Antoine

> 
> 
> -----Original Message-----
> From: users <users-bounces at lists.scilab.org> On Behalf Of Stéphane Mottelet
> Sent: Friday, June 19, 2020 10:15 AM
> To: users at lists.scilab.org
> Subject: Re: [Scilab-users] scilab 6.1 crashes when trying to load big matfile (loadmatfile)
> 
> it's the loadmatfile that crashes (here on Scilab-branch-6.1 under OSX, 
> with 16Gb ram)
> 
>    "savematfile('a28.mat','a28');"
> scilab-cli-bin(3310,0x115f1f5c0) malloc: can't allocate region
> *** mach_vm_map(size=18446744071562067968) failed (error code=3)
> scilab-cli-bin(3310,0x115f1f5c0) malloc: *** set a breakpoint in 
> malloc_error_break to debug
> 
> Same crash with Scilab-branch-6.1 under Ubuntu 18.04, with 128Gb ram:
> 
>    "a28=[1:2^28];"
> ATTENTION : Option -v7 ajoutée.
> 
>    "savematfile('a28.mat','a28');"
> Segmentation fault (core dumped)
> 
> S.
> 
> Le 19/06/2020 à 08:57, Antoine Monmayrant a écrit :
> > Hello all,
> >
> >
> > Here is a small script that systematically crashes scilab on my machine:
> >
> >
> > ////////////////////////////////
> >
> > // on my machine with 8Gb or ram and usual workload, n=28 crashes scilab
> > n=[24,26,28];
> >
> > for i=n
> >
> >     disp('---- '+string(i)+' ----');
> >     execstr('a'+string(i)+'=[1:2^'+string(i)+'];')
> >     disp('a'+string(i)+'=[1:2^'+string(i)+'];')
> > execstr("savematfile(''a"+string(i)+".mat'',''a"+string(i)+"'');")
> > disp("savematfile(''a"+string(i)+".mat'',''a"+string(i)+"'');")
> >     execstr("loadmatfile(''a"+string(i)+".mat'');")
> >     disp("loadmatfile(''a"+string(i)+".mat'');")
> >     disp('---- OK ----');
> >
> > end
> >
> 
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