Re: SIGSEGV problem

[Martin Pala]

Jan-Henrik Haukeland wrote:

> Christian Hopp <address@hidden> writes:
>
>  
>
> > On Thu, 14 Aug 2003, Jan-Henrik Haukeland wrote:
> >
> >    
> >
> > > I ran a fast test with efence and managed to reproduce the SIGSEGV (it
> > > may be more). SIGSEGV is thrown in process/common.c:connectchild()
> > > from this line:
> > >
> > >  parent->children[parent->children_num - 1] = (struct myprocesstree *) child;
> > >
> > >
> > > > From my gdb/efence session:
> > >
> > >  Program received signal SIGSEGV, Segmentation fault.
> > >  [Switching to Thread 1024 (LWP 1269)]
> > >  0x0805b340 in connectchild (parent=0x41143fa0, child=0x41144740)
> > >      at process/common.c:232
> > >
> > >  (gdb) p *parent->children
> > >  Cannot access memory at address 0x41365fcc
> > >
> > >  (gdb) p parent->children[parent->children_num - 1]
> > >  Cannot access memory at address 0x41365ffc
> > >
> > > I suspect it's caused by trying to access something outside the
> > > array. Maybe Christian can debug this since it's his code :) I'm of to
> > > bed, it's late.
> > >      
> > Strange... I just had a look at the code... and it IMHO impossible to
> > access memory which is not allocated at this position!
> >
> > I do a xcalloc of parent->children_num entities of pointers and it has to
> > be possible to access the last one (parent->childen_num - 1)... or?  Or is
> > it being deleted while this happens... somekind of race condition???
> >    
>
> I think it must have been a race condition of some sort. The strange
> thing is that I cannot reproduce the problem after I added the signal
> block code. Maybe that was it and it is fixed!? Do any of you get any
> more SIGSEGV now? Martin?
>
>  
It seems you've fixed the main reason :)

I did 2170 tests of which none failed.

Martin