Audacious

Interesting. I grep'ped for QFontDatabase in our code, and we don't use it directly.

Can you provide a debugger backtrace of the crash? Also, what version of Qt are you using?

Edit: saw that you already provided Qt versions, thanks.

Some others were having a similar issue in Fedora 33 apparently:
https://redmine.audacious-media-player.org/boards/1/topics/2748

Based on the workaround in that thread, can you try uninstalling qt5-qtpbfimageformat (it's not required for Audacious) and see if that fixes the issue?

John Lindgren wrote:

Some others were having a similar issue in Fedora 33 apparently:
https://redmine.audacious-media-player.org/boards/1/topics/2748

Based on the workaround in that thread, can you try uninstalling qt5-qtpbfimageformat (it's not required for Audacious) and see if that fixes the issue?

Ah! I did a quick DDG for that error message and didn't see anything salient; I didn't even know Audacious had forums. Nothing else on my system required qtpbfimageformat ("Qt image plugin for displaying Mapbox vector tiles"), so it was no problem to remove. That fixes the crash.

I've never worked with Mapbox directly, I have no idea what pulled in that library. Suspicious.

Thanks for the quick response, enjoy your weekend!

Okay I was able to reproduce here on Arch Linux after installing qt5-pbfimageplugin from AUR.

The backtrace here is:

#0  0x00007ffff772134c in __pthread_kill_implementation () at /usr/lib/libc.so.6
#1  0x00007ffff76d44b8 in raise () at /usr/lib/libc.so.6
#2  0x00007ffff76be534 in abort () at /usr/lib/libc.so.6
#3  0x00007ffff7208ee4 in qt_assert(char const*, char const*, int) () at /usr/lib/libQt5Core.so.5
#4  0x00007fffe1864884 in  () at /usr/lib/libQt5Gui.so.5
#5  0x00007fffcc6d9767 in fonts() () at src/font.cpp:62
#6  0x00007fffcc6dc6ad in matchFamily (family=...) at src/font.cpp:101
#7  Font::fromJsonArray(QJsonArray const&) (json=...) at src/font.cpp:123
#8  0x00007fffcc6d3402 in Style::Layer::Layout::Layout(QJsonObject const&)
    (this=0x7fffffffd160, json=..., this=<optimized out>, json=<optimized out>) at src/style.cpp:369
#9  0x00007fffcc6d5823 in Style::Layer::Layer(QJsonObject const&)
    (this=0x7fffffffd560, json=..., this=<optimized out>, json=<optimized out>) at src/style.cpp:500
#10 0x00007fffcc6d67fc in Style::load(QString const&) (this=<optimized out>, fileName=<optimized out>)
    at src/style.cpp:598
#11 0x00007fffcc6d80e4 in PBFPlugin::PBFPlugin() (this=0x5555575a8810, this=<optimized out>) at src/pbfplugin.cpp:16
#12 0x00007fffcc6e7ff7 in qt_plugin_instance() () at /usr/src/debug/QtPBFImagePlugin-2.3/moc_pbfplugin.cpp:124
#13 0x00007ffff73f08e0 in  () at /usr/lib/libQt5Core.so.5
#14 0x00007ffff73ea635 in QFactoryLoader::instance(int) const () at /usr/lib/libQt5Core.so.5
#15 0x00007fffe191776d in  () at /usr/lib/libQt5Gui.so.5
#16 0x00007fffe1918f44 in  () at /usr/lib/libQt5Gui.so.5
#17 0x00007fffe191a178 in QImageReader::read(QImage*) () at /usr/lib/libQt5Gui.so.5
#18 0x00007fffe191b30b in QImageReader::read() () at /usr/lib/libQt5Gui.so.5
#19 0x00007fffe18ff47e in QImage::load(QString const&, char const*) () at /usr/lib/libQt5Gui.so.5
#20 0x00007fffcca6b5c0 in skin_load_pixmap_id (path=0x5555555b1ce0 "/usr/share/audacious/Skins/Default", id=SKIN_MAIN)
    at skin.cc:108
#21 skin_load_pixmaps (path=0x5555555b1ce0 "/usr/share/audacious/Skins/Default") at skin.cc:212
#22 skin_load_data (path=0x5555555b1ce0 "/usr/share/audacious/Skins/Default") at skin.cc:244
#23 skin_load(char const*) (path=0x5555555b1ce0 "/usr/share/audacious/Skins/Default") at skin.cc:270
#24 0x00007fffcca68653 in load_initial_skin () at plugin.cc:120
#25 QtSkins::init() (this=<optimized out>) at plugin.cc:169
#26 0x00007ffff7f55625 in interface_load (plugin=0x5555555be4a0) at interface.cc:72
#27 iface_plugin_set_current(PluginHandle*) (plugin=0x5555555be4a0) at interface.cc:142
#28 0x00007ffff7f6767b in start_plugin(PluginType, PluginHandle*, bool)
    (type=type@entry=PluginType::Iface, p=p@entry=0x5555555be4a0, secondary=secondary@entry=false)
    at ../libaudcore/templates.h:224
#29 0x00007ffff7f67a36 in start_required (type=PluginType::Iface) at plugin-init.cc:136
#30 start_plugins(PluginType) (type=type@entry=PluginType::Iface) at plugin-init.cc:169
#31 0x00007ffff7f67c86 in start_plugins_two() () at plugin-init.cc:210
#32 0x00007ffff7f6d0b2 in aud_run() () at runtime.cc:342
#33 0x0000555555561c5d in main(int, char**) (argc=<optimized out>, argv=0x7fffffffe8e8) at main.cc:420

Working on a fix.