From: j DOT aldrich6 AT genie DOT com
Message-Id: <199604110429.AA236316991@relay1.geis.com>
Date: Thu, 11 Apr 96 04:19:00 UTC 0000
To: djgpp AT delorie DOT com
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Subject: Re: malloc crash

Reply to message 3313007    from JESUS AT MATRUST on 04/10/96  5:07AM


>The simple/sample program I posted it's the minimum number of instructions to
>generate the error (not a way to allocating memory).
>
>Thanks for your answer.
>
>Jesus.

No problem.  I just tried the same exact program and it crashed in exactly
the same place as yours!  (i=1027).  I tried running it through gdb and it
still crashed, but at i=997, not 1027.  What's more, it crashes not only itself
but every program associated with it!  When I ran just the image using
go32-v2, it nuked go32 at the same place.  When I tried running it through
redir to save a copy of the core dump, it crashed redir, too.

I did, however, run symify on the dump, and got the following stack trace:

_malloc+308
_malloc 177
_main+22, line 12 of test.c
___crt1_startup+115

All the programs it "brought down with it" also died at that exact point
(malloc+308).  It seems that under CWSDPMI, there is some limit to the
number of consecutive attempts one can make to call malloc()?!?  I
haven't tried the code under Windoze yet.  What's odd is that I have a
large program that allocates thousands of memory blocks, totalling
many megabytes, and it has never had any problem.  It uses calloc(),
though, rather than malloc() - could this be significant?

In case anybody is curious, I run a 486DX2/66, with 8 MB of RAM (approx.
5 MB free), and somewhere around 8-10 MB of disk space free.  I have
never had any problems with my setup or finding files, and what go32-v2
reports looks normal.

The code:

--- cut here ---

#include <stdio.h>
#include <malloc.h>


int main( void )
{
    int i;

    for ( i = 0; i < 5000; i++ )
    {
        malloc( 10000 );
        printf( "%d\n", i );
    }

    return 0;
}

--- end ---