[rrd-developers] rrdtool: *** glibc detected *** free(): invalid pointer: 0x08056450 ***

[Sebastian Harl]

Hi Bernhard,

On Wed, Jun 11, 2008 at 11:36:50PM +0200, Bernhard Fischer wrote:
> On Wed, Jun 11, 2008 at 10:28:47PM +0200, Sebastian Harl wrote:
> >collectd [1] is using "long long"'s in a couple of
> >places and it's known to compile and run on quite a few different
> >architectures.
> 
> I'm not talking about whether it runs or not, i'm talking about how much
> penalty you pay for using it on arches that don't do it natively.
> Folks are adding 256bit support for certain areas and codes, still you
> don't want to *emulate* 256bit support or anything else on a let's say
> 32bit host or even 64bit hosts.

I see your point now. I don't know how much impact 64 bits file offsets
would introduce. I cannot image that most people will really care about
it. Do you know of any performance tests? I would image that e.g. IO has
a _much_ larger effect...

Anyway, the patch I introduced in that other thread allows for disabling
LFS using a configure option. I think that any calculations that are
related to file offsets should be done using off_t's (i.e. that would
include the calculation of timestamps which are later used to calculate
some offsets) - then LFS could globally be disabled or enabled easily.
What do you think?

> >> We can test if it will wrap and should be (possibly) able to
> >> precalculate it here instead of later on.
> >
> >I'm not sure what you wanted to say with that... If it wraps and we
> >don't use any data types that are able to cope with that, I don't think
> >there's anything else we can do but bail out with an error message.
> 
> I'm not talking about an overflow but wrap, really.
> $ grep wrap src/*fetch*
> If it doesn't overflow, it would wrap, so prevent it from overflowing in
> the first place, that's what i ment. See?

Okay - how do you suggest to do that? ;-)

Cheers,
Sebastian

-- 
Sebastian "tokkee" Harl +++ GnuPG-ID: 0x8501C7FC +++ http://tokkee.org/

Those who would give up Essential Liberty to purchase a little Temporary
Safety, deserve neither Liberty nor Safety.         -- Benjamin Franklin

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