[Rd] memory leak in png()

[Martin Maechler]

>>>>> Edward Ionides 
>>>>>     on Mon, 16 Jan 2023 09:04:49 -0500 writes:

    > Hi all,

    > Yesterday I discovered what seems to me like a memory leak in png() so I'm
    > reporting it in case that is helpful. Here is a small reproducible example:

    > R -d "valgrind --tool=memcheck --track-origins=yes --leak-check=full"
    > --vanilla -e "png(filename='p.png'); plot(1:10); dev.off()"
    > ## HAS LEAK
    > ==1021711== LEAK SUMMARY:
    > ==1021711==    definitely lost: 9,216 bytes in 30 blocks
    > ==1021711==    indirectly lost: 19,370 bytes in 838 blocks
    > ==1021711==      possibly lost: 3,868 bytes in 8 blocks

    > R -d "valgrind --tool=memcheck --track-origins=yes --leak-check=full"
    > --vanilla -e "pdf(file='p.pdf'); plot(1:10); dev.off()"
    > ## NO LEAK
    > ==1031300== LEAK SUMMARY:
    > ==1031300==    definitely lost: 0 bytes in 0 blocks
    > ==1031300==    indirectly lost: 0 bytes in 0 blocks
    > ==1031300==      possibly lost: 0 bytes in 0 blocks

I can reproduce, although I need to have the memcheck options in ~/.valgrindrc
The same happens if grid-based graphics is used and for the
latest R-devel :

R-devel -d valgrind --vanilla -e 'png("p.png");lattice::xyplot(1~1);dev.off()'

Using  png() shows leak
using  pdf()  is fine (0 bytes lost)


Looking at the full report (--leak-check=full  --track-origins=true
as 2 lines in ~/.valgrindrc ) I see several origins tracked to
internal malloc code,
but then also e.g.,

==1410108== 96 bytes in 1 blocks are possibly lost in loss record 700 of 3,037
==1410108==    at 0x484A464: calloc (vg_replace_malloc.c:1328)
==1410108==    by 0x159EA3A0: g_malloc0 (gmem.c:155)
==1410108==    by 0x15A3AB8C: g_rc_box_alloc_full.constprop.0 (grcbox.c:234)
==1410108==    by 0x1600A6C9: UnknownInlinedFun (pangofc-fontmap.c:899)
==1410108==    by 0x1600A6C9: UnknownInlinedFun (pangofc-fontmap.c:2145)
==1410108==    by 0x1600A6C9: pango_fc_font_map_load_fontset (pangofc-fontmap.c:2245)
==1410108==    by 0x158E7474: UnknownInlinedFun (itemize.c:892)
==1410108==    by 0x158E7474: UnknownInlinedFun (itemize.c:952)
==1410108==    by 0x158E7474: pango_itemize_with_font (itemize.c:1564)
==1410108==    by 0x158FA89E: pango_layout_check_lines.part.0.lto_priv.0 (pango-layout.c:4894)
==1410108==    by 0x158EF4DB: UnknownInlinedFun (pango-layout.c:4786)
==1410108==    by 0x158EF4DB: pango_layout_get_line (pango-layout.c:1715)
==1410108==    by 0x1B5E441F: PG_text_extents (cairoFns.c:1487)
==1410108==    by 0x1B5E441F: PangoCairo_StrWidth (cairoFns.c:1565)
==1410108==    by 0x4CEBE6: GEStrWidth (engine.c:2615)
==1410108==    by 0x4CEBE6: GEStrWidth (engine.c:2578)
==1410108==    by 0x1BE12D11: textRect (util.c:198)
==1410108==    by 0x1BDFAF19: gridText (grid.c:3740)
==1410108==    by 0x1BE01FAB: L_textBounds (grid.c:3892)

which (from the bottom up) shows  package grid C code,
then R main but infrastructure for grDevices ("GEStrWidth (engine.c)")  and
subdirectory grDevices/src/cairo/cairoFns.c
and then goes into system cairo or pangocairo libraries,
which here (Linux Fedora 36) are (I thik)

	libpangocairo-1.0.so.0 
	libpango-1.0.so.0 

{as they are stripped, I don't know how to check }

To *fix* this I also have to defer to others.

Thank you for the report,
Martin

--
Martin Maechler
ETH Zurich  and  R Core team


    > For some context, I am running R4.2.2. My goal was to run valgrind on the
    > latest version of my spatPomp package. A memory leak was detected by
    > rhub::check_with_valgrind(). I then tracked down the problem by running
    > valgrind locally and in the end it seemed to come down to a problem with
    > png(). This was used in the spatPomp unit tests while testing the plot
    > method. I can use pdf() instead, but the point here is to report the issue
    > in case it is not known.

    > I'm new to R package development and happy to accept any advice.

    > Thanks,
    > Ed

    > Edward L. Ionides
    > Associate Chair for Undergraduate Studies and Professor,
    > Department of Statistics, University of Michigan
    > 1085 South University, Ann Arbor, MI 48109-1107
    > email: ionides using umich.edu
    > phone: 734 615 3332
    > office: 453 West Hall

    > [[alternative HTML version deleted]]

    > ______________________________________________
    > R-devel using r-project.org mailing list
    > https://stat.ethz.ch/mailman/listinfo/r-devel