since shortly my gnome shell crashes. All running applications were closed, for a short time the screen is black and I return to the login shell. I have no idea what program causes this error as it seems to happen accidentally. I attached the dmesg output for two crashes. It appears always a segfault. Mostly the error occurs when VirtualBox runs for a while. I am running Arch64 with Gnome 3.22.
Thank you for your advice.