Date: Sat, 20 Sep 2008 07:04:03 -0700 (PDT) From: Unga <unga888@yahoo.com> To: Giorgos Keramidas <keramida@ceid.upatras.gr> Cc: freebsd-questions@freebsd.org, Nash Nipples <trashy_bumper@yahoo.com> Subject: Re: Segmentation fault when free [SOLVED] Message-ID: <55974.31287.qm@web57001.mail.re3.yahoo.com> In-Reply-To: <87bpyj9qi9.fsf@kobe.laptop>
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--- On Sat, 9/20/08, Giorgos Keramidas <keramida@ceid.upatras.gr> wrote:
> > ktrace.out shows:
> > malloc_init()
> > 0x8103400 = malloc(1024)
> > malloc_init()
> > malloc_init()
> > 0x810b0b0 = malloc(400)
> > :
> > so many malloc
> > :
> > so many free
> > :
> > malloc/free combinations
> > :
> > free(0xbfbfc9c9)
> >
> > 1. This clearly shows my program is trying to free a
> memory that has
> > not been allocated. How it could have happened?
>
> Aha. This looks remarkably like an address in the runtime
> stack. It
> usually happens when you have a function that returns the
> address of a
> 'local' variable, instead of a newly allocated heap
> area, i.e.:
>
> char *
> function(void)
> {
> char buffer[100];
>
> return buf;
> }
>
This was indeed the case, worst yet, I was trying to free a part of the buffer (as per your example above) by mistake which was not allocated by malloc.
Thank you all who helped me.
Best regards
Unga
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