Re: [Gnuplot-info] glibc detected double free

[Hans-Bernhard B. <HBB...@t-...>]

On 05.04.2011 20:07, Olaf Till wrote:

> with gnuplot-4.4.0 and -4.4.3, and with the cvs version of 2011-03-31,
> glibc detects a double free. This happens regularly with the same
> types of commands (i.e. plotting certain data in a certain way from
> Octave), but not reproducibly with an exact procedure. Maybe there is
> a racing condition involved (?) (but Gnuplot probably gets the correct
> commands over the pipe, since Octave writes to the pipe blocking),
> since it does not occur from an ssh login.

Any chance you could exercise that with valgrind, too?  The reports from 
valgrind are much more detailed.

In the case at hand, that backtrace is quite obviously broken.

> unset_tics
> /home/olaf/gnuplot-cvs/gnuplot/src/unset.c:1179
>
> unset_minitics
> /home/olaf/gnuplot-cvs/gnuplot/src/unset.c:1156

> which seems weird to me, since unset_minitics does not seem to call
> unset_tics;

Not only does it not call unset_tics() --- it doesn't call _any_ function.

 > but gnuplot had been compiled with -O2.

That really doesn't matter.  What we're looking at here must be 
something else.  That call stack got corrupted before glibc got to 
analyse it properly.