Waybar crashes repeatedly in the same way at random times in wcscoll_l()

[fmgh001]

Here is the stack trace

Thread 1 "waybar" received signal SIGSEGV, Segmentation fault.
0x00007ffff61fe3ea in wcscoll_l () from /lib64/libc.so.6
(gdb) bt
#0 0x00007ffff61fe3ea in wcscoll_l () at /lib64/libc.so.6
#1 0x00007ffff68f3d0f in g_utf8_collate () at /usr/lib64/libglib-2.0.so.0
#2 0x00005555555e899f in Glib::operator!=(Glib::ustring const&, Glib::ustring const&) (rhs=..., lhs=...) at /usr/include/glibmm-2.4/glibmm/ustring.h:1820
#3 waybar::modules::Custom::update() (this=0x555555904580) at ../Waybar-0.9.24/src/modules/custom.cpp:172
#4 0x000055555560e829 in operator() (__closure=) at ../Waybar-0.9.24/src/bar.cpp:783
#5 sigc::adaptor_functor<waybar::Bar::getModules(const waybar::Factory&, const std::string&, waybar::Group*)::<lambda()> >::operator() (this=) at /usr/include/sigc++-2.0/sigc++/adaptors/adaptor_trait.h:256
#6 sigc::internal::slot_call0<waybar::Bar::getModules(const waybar::Factory&, const std::string&, waybar::Group*)::<lambda()>, void>::call_it(sigc::internal::slot_rep ) (rep=0x555555a385a0) at /usr/include/sigc++-2.0/sigc++/functors/slot.h:136
#7 0x00007ffff76d238a in sigc::internal::signal_emit0<void, sigc::nil>::emit(sigc::internal::signal_impl) () at /usr/lib64/libglibmm-2.4.so.1
#8 0x00007ffff76d1c39 in Glib::DispatchNotifier::pipe_io_handler(Glib::IOCondition) () at /usr/lib64/libglibmm-2.4.so.1
#9 0x00007ffff76d4480 in Glib::IOSource::dispatch(sigc::slot_base*) () at /usr/lib64/libglibmm-2.4.so.1
#10 0x00007ffff76d3fb7 in Glib::Source::dispatch_vfunc(_GSource*, int ()(void), void*) () at /usr/lib64/libglibmm-2.4.so.1
#11 0x00007ffff68b5888 in () at /usr/lib64/libglib-2.0.so.0
#12 0x00007ffff68b8c97 in () at /usr/lib64/libglib-2.0.so.0
#13 0x00007ffff68b92e0 in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#14 0x00007ffff6af5ecd in g_application_run () at /usr/lib64/libgio-2.0.so.0
#15 0x00005555555af1fc in waybar::Client::main(int, char**) (this=this@entry=0x5555557efd00, argc=, argc@entry=1, argv=, argv@entry=0x7fffffffdef8) at /usr/include/glibmm-2.4/glibmm/refptr.h:259
#16 0x00005555555ad7d5 in main(int, char**) (argc=1, argv=0x7fffffffdef8) at ../Waybar-0.9.24/src/main.cpp:106

(gdb) i r
rax 0x5555557fa7b0 93824995010480
rbx 0x0 0
rcx 0xffffffb0 4294967216
rdx 0x42 66
rsi 0x0 0
rdi 0x5555559e80b0 93824997032112
rbp 0x5555559e80b0 0x5555559e80b0
rsp 0x7fffffffcda0 0x7fffffffcda0
r8 0x72 114
r9 0x0 0
r10 0x1 1
r11 0x68 104
r12 0x7fffffffcf50 140737488342864
r13 0x555555904780 93824996099968
r14 0x555555904668 93824996099688
r15 0x5555558ae6f0 93824995747568
rip 0x7ffff61fe3ea 0x7ffff61fe3ea <wcscoll_l+58>
eflags 0x10202 [ IF RF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0
k0 0x0 0
k1 0x0 0
k2 0x0 0
k3 0x0 0
k4 0x0 0
k5 0x0 0
k6 0x0 0
k7 0x0 0

=> 0x7ffff61fe3ea <wcscoll_l+58>: mov ecx,DWORD PTR [rbx]
0x7ffff61fe3ec <wcscoll_l+60>: test edx,edx
0x7ffff61fe3ee <wcscoll_l+62>: je 0x7ffff61ff22a <wcscoll_l+3706>
0x7ffff61fe3f4 <wcscoll_l+68>: test ecx,ecx
0x7ffff61fe3f6 <wcscoll_l+70>: je 0x7ffff61ff22a <wcscoll_l+3706>
0x7ffff61fe3fc <wcscoll_l+76>: mov rbx,QWORD PTR [rax+0x40]
0x7ffff61fe400 <wcscoll_l+80>: mov r15,QWORD PTR [rax+0x80]
0x7ffff61fe407 <wcscoll_l+87>: mov r8,QWORD PTR [rax+0x88]
0x7ffff61fe40e <wcscoll_l+94>: mov QWORD PTR [rsp+0x18],rbx
0x7ffff61fe413 <wcscoll_l+99>: mov rbx,QWORD PTR [rax+0x90]
0x7ffff61fe41a <wcscoll_l+106>: mov rax,QWORD PTR [rax+0x98]
0x7ffff61fe421 <wcscoll_l+113>: mov QWORD PTR [rsp+0x20],rbx
0x7ffff61fe426 <wcscoll_l+118>: mov QWORD PTR [rsp+0x8],rax
0x7ffff61fe42b <wcscoll_l+123>: test r15b,0x3
0x7ffff61fe42f <wcscoll_l+127>: jne 0x7ffff61ff2a1 <wcscoll_l+3825>
0x7ffff61fe435 <wcscoll_l+133>: test r8b,0x3

Looks like a null deref. If you need more details let me know.

[fmgh001]

Would love to learn more on why this is happening. I can provide more traces or inspection. This bug is very frequent.