While running Dota2 and moving around in the Panorama menus (most likely a technology based on Chromium) the game freezes and the system becomes unresponsive. The screen is stuck on a frame and I have to hard reset my system.
In systemlog the key lines written are as follows:
21:47:41 kernel: NVRM: GPU at PCI:0000:01:00: GPU-3d2e1720-3ac2-b3d0-73cf-e44dab47add3 21:47:41 kernel: NVRM: Xid (PCI:0000:01:00): 31, pid=1070, Ch 00000034, intr 10000000. MMU Fault: ENGINE CE2 HUBCLIENT_CE2 faulted @ 0x1_1db46000. Fault is of type FAULT_PTE ACCESS_TYPE_WRITE 21:47:48 kernel: nvidia-modeset: ERROR: GPU:0: Error while waiting for GPU progress: 0x0000917c:0 2:0:3624:3616
I will try to generate a proper nvidia-log next time it happens (need to enable logging in xorg first). It has been more and more frequent since recent Dota2 patches.
Below is the full log after I issued kill commands through SSH to attempt to kill the Steam client and eventually my X11 server (to no avail).
Reported the issue to Valve here.