Re: [Plplot-general] Memory leaks in several plplot functions

[Andrew R. <and...@us...>]

On Fri, Nov 23, 2012 at 09:48:58AM -0800, Alan Irwin wrote:
> On 2012-11-23 12:13-0000 Andrew Ross wrote:
> 
> > Alan,
> >
> > This is odd, because there definitely seems to be a bug in the plplot
> > code path for plotting text. I've just fixed it now. This gave
> > problems for both pngcairo and pscairo for me.
> 
> That is odd indeed that the valgrind run for me for pngcairo was fine,
> but not for you.  However, I have just run the same two tests again
> with your change (at revision 12279)
> 
> valgrind examples/c/x02c -dev pngcairo -o test.png -fam
> valgrind examples/c/x02c -dev pngcairo -o test.png
> 
> and all continues to be well for me.  However, I still get
> valgrind problems with pscairo, e.g.,
> 
> software@raven> valgrind --num-callers=40 \
> examples/c/x02c -dev pscairo -o test.ps
> ==4666== Memcheck, a memory error detector
> ==4666== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
> ==4666== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright
> info
> ==4666== Command: examples/c/x02c -dev pscairo -o test.ps
> ==4666== 
> ==4666== Invalid read of size 4
> ==4666==    at 0x74E2145: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E3742: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E3C20: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x75109C9: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E09DD: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x7511067: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C668B: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C6ACC: cairo_surface_finish (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74A1AD3: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C668B: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C679C: cairo_surface_destroy (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x6E019A9: plD_tidy_cairo (in
> /home/software/plplot_svn/HEAD/build_dir/drivers/cairo.so)
> ==4666==    by 0x4E4F0FE: c_plend1 (in
> /home/software/plplot_svn/HEAD/build_dir/src/libplplotd.so.11.0.0)
> ==4666==    by 0x4E4F162: c_plend (in
> /home/software/plplot_svn/HEAD/build_dir/src/libplplotd.so.11.0.0)
> ==4666==    by 0x400D8A: main (in
> /home/software/plplot_svn/HEAD/build_dir/examples/c/x02c)
> ==4666==  Address 0xb8280b8 is 8 bytes inside a block of size 11 alloc'd
> ==4666==    at 0x4C28BED: malloc (vg_replace_malloc.c:263)
> ==4666==    by 0x74E21F1: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E3742: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E3C20: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x75109C9: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74E09DD: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x7511067: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C668B: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C6ACC: cairo_surface_finish (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74A1AD3: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C668B: ??? (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x74C679C: cairo_surface_destroy (in
> /usr/lib/x86_64-linux-gnu/libcairo.so.2.11200.2)
> ==4666==    by 0x6E019A9: plD_tidy_cairo (in
> /home/software/plplot_svn/HEAD/build_dir/drivers/cairo.so)
> ==4666==    by 0x4E4F0FE: c_plend1 (in
> /home/software/plplot_svn/HEAD/build_dir/src/libplplotd.so.11.0.0)
> ==4666==    by 0x4E4F162: c_plend (in
> /home/software/plplot_svn/HEAD/build_dir/src/libplplotd.so.11.0.0)
> ==4666==    by 0x400D8A: main (in
> /home/software/plplot_svn/HEAD/build_dir/examples/c/x02c)
> ==4666== 
> ==4666== 
> ==4666== HEAP SUMMARY:
> ==4666==     in use at exit: 387,975 bytes in 2,703 blocks
> ==4666==   total heap usage: 19,606 allocs, 16,903 frees, 4,869,363
> bytes allocated
> ==4666== 
> ==4666== LEAK SUMMARY:
> ==4666==    definitely lost: 4,440 bytes in 8 blocks
> ==4666==    indirectly lost: 16,160 bytes in 503 blocks
> ==4666==      possibly lost: 56,513 bytes in 157 blocks
> ==4666==    still reachable: 310,862 bytes in 2,035 blocks
> ==4666==         suppressed: 0 bytes in 0 blocks
> ==4666== Rerun with --leak-check=full to see details of leaked memory
> ==4666== 
> ==4666== For counts of detected and suppressed errors, rerun with: -v
> ==4666== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 7 from 7)
> 
> If you cannot replicate that, then presumably the update between my
> version (pango-1.30.0-1, cairo-1.12.2-2) and yours (or else an
> improved valgrind suppressions file in your case) solved this problem,
> and the issue is nothing for us to worry about.

Alan,

I don't see this warning at all. Instead, for both pscairo and pngcairo 
I see invalid reads inside pango_layout_get_pixel_size called from 
text_end_cairo. The block is allocated from within the same function. 
This, along with the fact you don't see the messages makes me suspect 
that this is a cairo / pango leak. I suspect yours is also a cairo 
related problem for similar reasons. It's just our different respective
versions have different problems!

There are still a number of smaller leaks in both our cases that may be 
worth some further checks by someone with a better grasp of cairo.

Andrew