Segfault randomly related to wireplumber module

[BBaoVanC]

Sometimes waybar just crashes, not sure of the direct cause. I am running version 0.12.0.

I didn't have log output redirected anywhere so I only have the coredump right now. I'll update if I can get log output of this happening.

Here is the backtrace:

(gdb) bt
#0  0x00005a966b3c292d in waybar::modules::Wireplumber::onMixerApiLoaded (p=<optimized out>, res=<optimized out>, self=0x5a969c558af0)
    at ../src/modules/wireplumber.cpp:282
#1  0x00007388dc5ee8ac in g_task_return_now (task=0x5a969c4b0110) at ../glib/gio/gtask.c:1361
#2  0x00007388dc5ee8f5 in complete_in_idle_cb (task=0x5a969c4b0110) at ../glib/gio/gtask.c:1375
#3  0x00007388dc3f2919 in g_main_dispatch (context=0x5a969bc770b0) at ../glib/glib/gmain.c:3357
#4  0x00007388dc4555d7 in g_main_context_dispatch_unlocked (context=0x5a969bc770b0) at ../glib/glib/gmain.c:4208
#5  g_main_context_iterate_unlocked.isra.0 (context=context@entry=0x5a969bc770b0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at ../glib/glib/gmain.c:4273
#6  0x00007388dc3f1e15 in g_main_context_iteration (context=context@entry=0x5a969bc770b0, may_block=may_block@entry=1) at ../glib/glib/gmain.c:4338
#7  0x00007388dc6240b6 in g_application_run (application=0x5a969bc80a50, argc=<optimized out>, argv=0x7ffc272990b8) at ../glib/gio/gapplication.c:2715
#8  0x00005a966b2eb4fd in waybar::Client::main (this=0x5a969bc43cc0, argc=<optimized out>, argv=<optimized out>)
    at /usr/include/glibmm-2.4/glibmm/refptr.h:259
#9  0x00005a966b2e90f5 in main (argc=3, argv=0x7ffc272990b8) at ../src/main.cpp:107

Code in frame 0:

(gdb) f 0
#0  0x00005a966b3c292d in waybar::modules::Wireplumber::onMixerApiLoaded (p=<optimized out>, res=<optimized out>, self=0x5a969c558af0)
    at ../src/modules/wireplumber.cpp:282
282	   throw std::runtime_error(error->message);
(gdb) l
277	
278	 success = wp_core_load_component_finish(self->wp_core_, res, nullptr);
279	
280	 if (success == FALSE) {
281	   spdlog::error("[{}]: mixer API load failed", self->name_);
282	   throw std::runtime_error(error->message);
283	 }
284	
285	 spdlog::debug("[{}]: loaded mixer API", self->name_);
286	 g_ptr_array_add(self->apis_, ({

[BBaoVanC]

It happens reliably immediately after I take a screenshot in Hyprland with grimblast. Not sure of the actual cause. The backtrace might be deceiving because I think there's undefined behavior. All the fields on self in that method are null.

[sayhilel]

yeah seems like a regression, temp fix is to just use the pulseaudio module and not the wireplumber.

[RobertMueller2]

I think that was introduced here: https://github.com/Alexays/Waybar/pull/2919/files, lines 263-265 (old) and 279-281 (new). If I read this correctly, error is still a NULL pointer when passed to the throw statement.

Perhaps line 277 (new) can be changed to success = wp_core_load_component_finish(self->wp_core_, res, &error);. But I don't know the module, or the API, and I can't reproduce the issue either, and I might just be talking nonsense anyway.

@tokyovigilante can you have a look, please?