When 2D acceleration is enabled through nouveau (default), the computer freezes and becomes unresponsive. Occasionally remote access is still possible, but this is not always the case. In most cases, I wasn't doing anything particularly graphically intensive. In one instance, it locked up while I was away, simply streaming audio from the machine.

Adding the kernel parameter `nouveau.noaccel=1` prevents this failure.
Kernel logging on this failure is hit-or-miss... sometimes I get a `kmem_cache_alloc_trace` (as seen in the attached log) and others the logs stop after the line following `general protection fault, probably for non-canonical address`.

I spent some time running through some nouveau tweaks with a developer in #nouveau—they ultimately concluded that it is not a nouveau bug, and that nouveau is simply getting hosed by another problem (see a similar trace for btrfs in the kernel log).

I first encountered this at least a year ago, but at the time simply disabled 2d accel... as such, I am not sure what the first affected version is. Nonetheless, I have yet to run into this using the LTS kernel, thus my belief that this is a kernel issue.

My GPU is a GeForce GTX 670 (Kepler)

Attached are a (truncated; see note for full text) kernel log (with `drm.debug=14 log_buf_len=16M`, per nouveau debug suggestions), Xorg log, and my (minimal) Xorg config.