~ $ gdb kmail
GNU gdb (Gentoo 8.1 p1) 8.1
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Reading symbols from kmail...Reading symbols from /usr/lib64/debug//usr/bin/kmail.debug...done.
done.
(gdb) break main
Breakpoint 1 at 0x2900: file /usr/src/debug/kde-apps/kmail-18.12.1/kmail-18.12.1/src/main.cpp, line 121.
(gdb) run
Starting program: /usr/bin/kmail
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Breakpoint 1, main (argc=1, argv=0x7fffffffdb08) at /usr/src/debug/kde-apps/kmail-18.12.1/kmail-18.12.1/src/main.cpp:121
121     {
(gdb) continue
Continuing.
[New Thread 0x7fffc9f4b700 (LWP 16081)]
[New Thread 0x7fffbd511700 (LWP 16086)]
[New Thread 0x7fffbcd10700 (LWP 16087)]
[New Thread 0x7fffb75ef700 (LWP 16088)]
[New Thread 0x7fffb6dee700 (LWP 16089)]
[New Thread 0x7fffb65ed700 (LWP 16090)]
[New Thread 0x7fffa208a700 (LWP 16101)]
[New Thread 0x7fffa1023700 (LWP 16123)]
Nouveau openGL driver detected. Qt WebEngine will disable usage of the GPU.
Note: you can set the QT_WEBENGINE_DISABLE_NOUVEAU_WORKAROUND
environment variable before running this application, but this is
not recommended since this usually causes applications to crash as
Nouveau openGL drivers don't support multithreaded rendering
[New Thread 0x7fff9b8b9700 (LWP 16124)]
[New Thread 0x7fff9b0b8700 (LWP 16129)]
[New Thread 0x7fff9a8b7700 (LWP 16130)]
[New Thread 0x7fff9a0b6700 (LWP 16131)]
[New Thread 0x7fff998b5700 (LWP 16132)]
[New Thread 0x7fff990b4700 (LWP 16133)]
[New Thread 0x7fff988b3700 (LWP 16134)]
[New Thread 0x7fff77fff700 (LWP 16135)]
[New Thread 0x7fff6ffff700 (LWP 16136)]
[New Thread 0x7fff777fe700 (LWP 16137)]
[New Thread 0x7fff76ffd700 (LWP 16138)]
[New Thread 0x7fff767fc700 (LWP 16139)]
[New Thread 0x7fff75ffb700 (LWP 16140)]
[New Thread 0x7fff757fa700 (LWP 16141)]
[New Thread 0x7fff74ff9700 (LWP 16142)]
[New Thread 0x7fff6f7fe700 (LWP 16143)]
[New Thread 0x7fff6effd700 (LWP 16144)]
[New Thread 0x7fff6e7fc700 (LWP 16145)]
[New Thread 0x7fff6dffb700 (LWP 16146)]
[New Thread 0x7fff6d7fa700 (LWP 16147)]
[New Thread 0x7fff6cff9700 (LWP 16148)]
[New Thread 0x7fff22866700 (LWP 16171)]
[New Thread 0x7fff20abd700 (LWP 16188)]
[New Thread 0x7fff2317b700 (LWP 16190)]
[New Thread 0x7ffe9a3c1700 (LWP 16208)]
QIODevice::read (QLocalSocket): device not open
QIODevice::read (QLocalSocket): device not open
[Thread 0x7fff2317b700 (LWP 16190) exited]
QIODevice::read (QLocalSocket): device not open

Thread 1 "kmail" received signal SIGSEGV, Segmentation fault.
0x00000000000000f1 in ?? ()
(gdb)