[Debichem-devel] Bug#996006: ghemical: Segmentation fault when starting

[Bernhard Übelacker]

Dear Maintainer,
I could reproduce this inside a minimal qemu VM.
Below [1] is a backtrace one instruction before the crash.
It looks like this "font" object has the create_hb_font
function pointer never initialized.
It also crashes with LANG=C set.

Unfortunately to me it is not certain if this is
an issue with pango or the application.
Additionally it looks like there were some changes in
pango (e.g. [2]) between the versions of bullseye and buster.
In the latter no such crash is observable.

Kind regards,
Bernhard


[1]
     (rr) reverse-stepi
     0x00007fb5b32b8c33 in pango_font_get_hb_font (font=font at entry=0x558dd5dcdb30) at ../pango/fonts.c:1928
     1928      priv->hb_font = PANGO_FONT_GET_CLASS (font)->create_hb_font (font);
     1: x/i $pc
     => 0x7fb5b32b8c33 <pango_font_get_hb_font+83>:  call   *0xc0(%r12)
     (rr) bt
     #0  0x00007fb5b32b8c33 in pango_font_get_hb_font (font=font at entry=0x558dd5dcdb30) at ../pango/fonts.c:1928
     #1  0x00007fb5b32d4e13 in pango_font_get_hb_font_for_context (context=0x7ffc5f4f04c0, font=0x558dd5dcdb30) at ../pango/pangofc-shape.c:277
     #2  pango_hb_shape (font=0x558dd5dcdb30, item_text=item_text at entry=0x7fb5b32dff4e <lang_pool+1006> "Zwölf Boxkämpfer jagen Viktor quer über den großen Sylter Deich.", item_length=item_length at entry=68, analysis=analysis at entry=0x7ffc5f4f0850, glyphs=glyphs at entry=0x558dd5acc6c0, paragraph_text=paragraph_text at entry=0x7fb5b32dff4e <lang_pool+1006> "Zwölf Boxkämpfer jagen Viktor quer über den großen Sylter Deich.", paragraph_length=68) at ../pango/pangofc-shape.c:345
     #3  0x00007fb5b32d466f in pango_shape_with_flags (item_text=0x7fb5b32dff4e <lang_pool+1006> "Zwölf Boxkämpfer jagen Viktor quer über den großen Sylter Deich.", item_length=<optimized out>, paragraph_text=<optimized out>, paragraph_length=68, analysis=0x7ffc5f4f0850, glyphs=0x558dd5acc6c0, flags=PANGO_SHAPE_NONE) at ../pango/shape.c:205
     #4  0x00007fb5b32d4adb in pango_shape_full (item_text=<optimized out>, item_length=<optimized out>, paragraph_text=<optimized out>, paragraph_length=<optimized out>, analysis=analysis at entry=0x7ffc5f4f0850, glyphs=glyphs at entry=0x558dd5acc6c0) at ../pango/shape.c:96
     #5  0x00007fb5b32d4af0 in pango_shape (text=<optimized out>, length=<optimized out>, analysis=analysis at entry=0x7ffc5f4f0850, glyphs=glyphs at entry=0x558dd5acc6c0) at ../pango/shape.c:63
     #6  0x00007fb5b264b273 in itemize_string_foreach (font=font at entry=0x558dd5dcdb30, language=language at entry=0x0, str=<optimized out>, func=func at entry=0x7fb5b264b010 <get_subfonts_foreach>, data=data at entry=0x7ffc5f4f08f0) at pangox.c:777
     #7  0x00007fb5b264b9b4 in get_font_metrics_from_string (metrics=0xffffffffd60e1730, str=<optimized out>, language=0x0, font=0x558dd5dcdb30) at pangox.c:922
     #8  pango_x_font_get_metrics (font=0x558dd5dcdb30, language=0x0) at pangox.c:984
     #9  0x0000558dd55f4556 in pangofont_wcl::ogl_InitPangoFont(char const*) (this=0x558dd5c19bc0, fs=0x558dd5623360 "courier 12") at pangofont_wcl.cpp:79
     #10 0x0000558dd55f492a in oglview_wcl::InitGL() (this=0x558dd5c19bc0) at oglview_wcl.cpp:929
     #11 0x00007fb5b2c3eebe in base_wcl::LinkWnd(base_wnd*) (this=0x558dd5c19bc0, w=0x558dd5c18fa0) at base_wcl.cpp:111
     #12 0x0000558dd55eb93d in project::AddGraphicsClient(custom_camera*, bool) (this=this at entry=0x558dd5a83df0, cam=0x558dd5c8fae0, cam at entry=0x0, detached=detached at entry=false) at project.cpp:622
     #13 0x0000558dd561dc12 in gtk_project::DoSafeStart() (this=0x558dd5a83df0) at gtk_project.cpp:80
     #14 0x0000558dd561aed3 in gtk_app::gtk_app() (this=0x558dd59fde70) at gtk_app.cpp:450
     #15 0x0000558dd561b165 in gtk_app::GetAppX() () at gtk_app.cpp:465
     #16 0x0000558dd55d49d4 in main(int, char**) (argc=<optimized out>, argv=<optimized out>) at gtk_main.cpp:116
     (rr) x/1xg $r12+0xc0
     0x558dd60e1e70: 0x0000000000000000


[2]
     https://gitlab.gnome.org/GNOME/pango/-/commit/b5634799586ed8e3496ffc237b8d08e6d4e64d67