Looking more precisely at the backtrace in the core file, the culprit seems to be here:
#10 0x00007f1c4420b5b2 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6 #11 0x00007f1c3d68143f in nouveau_pushbuf_data () from /usr/lib/x86_64-linux-gnu/libdrm_nouveau.so.2 which appears in a different form in the journalctl output: août 13 11:31:51 lehrin gnome-shell[14075]: Xwayland: ../nouveau/pushbuf.c:723: nouveau_pushbuf_data: Assertion `kref' failed. This looks a lot like bug #929130, registered more than one year ago for libdrm-nouveau2 package. Luc
