Seg fault after 2 days of simulation

[Jan Kreft]

Dear all,

I've been making many long simulations during the last weeks and some
of them crashed with a seg fault after a long time. Since I have to
wait two days to reach the same time again in the sim, I'd like to
know what I should do to track this error down.

I'm really clueless as to what causes this crash, the same messages
have been called in the program thousands of times before. Why does it
go wrong after 56884 steps when it worked all the time before?

Here is the last line of sim output with the output from gdb:

diffusion at 56884 made 13 diffSteps totalling 5368215 steps

Program received signal SIGSEGV, Segmentation fault.
0x404134d8 in chunk_free (ar_ptr=0x4046d300, p=0x9c7bf90) at malloc.c:2942
malloc.c:2942: No such file or directory.
Current language:  auto; currently c
(gdb) bt
#0  0x404134d8 in chunk_free (ar_ptr=0x4046d300, p=0x9c7bf90) at malloc.c:2942
#1  0x40412c3e in malloc_extend_top (ar_ptr=0x4046d300, nb=72) at malloc.c:2464
#2  0x40413253 in chunk_alloc (ar_ptr=0x4046d300, nb=72) at malloc.c:2793
#3  0x40412d15 in __libc_malloc (bytes=64) at malloc.c:2561
#4  0x4019f672 in xmalloc (size=64) at xmalloc.c:13
#5  0x4018b409 in -[Zone(c) _allocIVars:] (self=0x81dc470, _cmd=0x40197c10, 
aClass=0x817d800) at Zone.m:28
#6  0x4017ddaa in +[CreateDrop(s) _createBegin:] (self=0x817d800, 
_cmd=0x817d840, aZone=0x81dc470) at Create.m:32
#7  0x80523aa in +[Mcr create] (self=0x817d800, _cmd=0x817d898) at Mcr.m:16
#8  0x8052d5a in -[Mcr intersectMcr:] (self=0x8282d98, _cmd=0x817d398, 
m=0x90c71c0) at Mcr.m:169
#9  0x8050e58 in -[Quad growMcr] (self=0x90c7188, _cmd=0x817d2e8) at Quad.m:325
#10 0x805066c in -[Quad addNode:] (self=0x8282d60, _cmd=0x818ac70, p=0x90c7188) 
at Quad.m:142
#11 0x809d94f in -[Bacillus reproduce] (self=0x9af8cc0, _cmd=0x818ac20) at 
Bacillus.m:756
#12 0x809d088 in -[Bacillus checkVolume] (self=0x9af8cc0, _cmd=0x818acb0) at 
Bacillus.m:662
#13 0x809dad8 in -[Bacillus step] (self=0x9af8cc0, _cmd=0x817d558) at 
Bacillus.m:780
#14 0x80521f5 in -[Quad substep] (self=0x96ccfb0, _cmd=0x817d568) at Quad.m:650
#15 0x8052257 in -[Quad substep] (self=0x9984580, _cmd=0x817d568) at Quad.m:655
#16 0x8052257 in -[Quad substep] (self=0x9396d18, _cmd=0x817d568) at Quad.m:655
#17 0x8052257 in -[Quad substep] (self=0x94c1320, _cmd=0x817d568) at Quad.m:655
#18 0x8052257 in -[Quad substep] (self=0x963c8d0, _cmd=0x817d568) at Quad.m:655
#19 0x8052257 in -[Quad substep] (self=0x97797e8, _cmd=0x817d570) at Quad.m:655
#20 0x80522b3 in -[Quad step] (self=0x8282d60, _cmd=0x817d580) at Quad.m:665
#21 0x805231f in -[Quad stepOn:] (self=0x8282d60, _cmd=0x818beb8, roundth=1) at 
Quad.m:672
#22 0x401817ac in -[Object(s) _perform:with:] (self=0x8282d60, _cmd=0x400b8070, 
aSel=0x818beb8, anObject1=0x1) at DefObject.m:521
#23 0x400a86e7 in -[ActionTo(1) __performAction::] (self=0x845fde0, 
_cmd=0x400bbb28, anActivity=0x9bb82a0) at Action.m:277
#24 0x400af75b in -[Activity(c) __run:] (self=0x9bb82a0, _cmd=0x400bbb10) at 
XActivity.m:185
#25 0x400af65d in -[Activity(c) __run:] (self=0x84625c8, _cmd=0x400bbb10) at 
XActivity.m:143
#26 0x400af65d in -[Activity(c) __run:] (self=0x8461bf0, _cmd=0x400bbb10) at 
XActivity.m:143
#27 0x400af65d in -[Activity(c) __run:] (self=0x8461000, _cmd=0x400bbaf8) at 
XActivity.m:143
#28 0x400af539 in -[Activity(c) _run] (self=0x8461000, _cmd=0x8183910) at 
XActivity.m:72
#29 0x80792a5 in -[GeckoControlSwarm go] (self=0x8259b08, _cmd=0x817ced8) at 
GeckoControlSwarm.m:315
#30 0x805013f in main (argc=4, argv=0xbffff7c4) at main.m:42
(gdb) 

And here is the relevant code:

#import <limits.h>
#import <math.h>
#import "Mcr.h"
#import "Stat.h"

// Defining the methods for an Mcr.
@implementation Mcr

//creating a null Mcr.  
+create
{
    id result;
    result = [[Mcr createBegin: globalZone] createEnd];
    [result setNullMcr];
    return result;                                      
}

-(void) drop
{
    [super drop];
}

-setNullMcr
{
    lx = INT_MAX;
    ux = INT_MIN;
    ly = INT_MAX;
    uy = INT_MIN;
    lz = INT_MAX;
    uz = INT_MIN;
    return self;
}

...........

What should I do to track this down further?

Many thanks, Jan.


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