Re: [Matplotlib-users] Segmentation fault under Agg

[John H. <jd...@gm...>]

On Wed, Sep 23, 2009 at 6:47 PM, Mike Nicolls <mic...@sr...> wrote:
> I've encountered a segmentation fault using the Agg backend when making
> and saving a png plot.  The segmentation fault does not seem to occur
> under different backends (e.g. Cairo).
>
> The sequence of commands amounts to making a plot, setting the limits of
> the plot, then saving the plot as a png using savefig.  If the value of
> one of the points is too large, a segmentation fault is generated.
> Obviously the simple work-around is to not plot the out-of-bounds
> points, but the segmentation fault is probably not the desired behavior!
>
> Below is an example, which generates a segmentation fault on matplotlib
> versions 0.99.0 (run on OS X 10.5.8) and 0.98.5.2 (run on Fedora 11 and
> CentOS 5.3).
>
> Can others reproduce this issue?

Thanks for the report -- I can confirm this on OSX and linux on svn HEAD

I've made minor tweaks to your test case to make it deterministic::

    import numpy as np
    import matplotlib
    matplotlib.use('Agg')
    import matplotlib.pyplot as plt

    xdata = np.arange(10.0)
    ydata = np.arange(10.0)

    xdata[3]=1.0e9  # comment out to avoid seg fault

    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.plot(xdata,ydata,'k.')
    ax.set_xlim(0.0,1.0)

    fig.savefig('test.png')


and added a bug report to :

  https://sourceforge.net/tracker/?func=detail&aid=2865490&group_id=80706&atid=560720

Platforms confirmed w/ bug:

home:~> uname -a
Darwin Macintosh-8.local 9.8.0 Darwin Kernel Version 9.8.0: Wed Jul 15
16:55:01 PDT 2009; root:xnu-1228.15.4~1/RELEASE_I386 i386

jdhunter@uqbar:~> uname -a
Linux uqbar 2.6.27-14-generic #1 SMP Tue Jun 30 19:54:46 UTC 2009
x86_64 GNU/Linux