Mono often crashes on newer Linux kernels.
Mono versions where this bug was tested and happens: 3.4, 3.8, 3.10
Linux kernels where Mono crashes: 3.14, 3.16
Linux kernels where Mono *doesn't* crash: 3.10, 3.11
Here's an example of one of the crashes: http://pastebin.com/Rcxy6WrS
(It was sent by a different user than me)
I've verified that the kernel is the problem by changing the kernel version back and forth on the same machine.
We have many people experiencing similar issues. http://opensimulator.org/mantis/view.php?id=7519
I made a number of tests with Mono 3.2.8 and 4.0.1 and can confirm the issue on 64-bit 3.13 and 3.16 kernels of Ubuntu 14.04.2 LTS (GNU/Linux 3.13.0-52-generic x86_64), Ubuntu 14.04.2 LTS (GNU/Linux 3.16.0-37-generic x86_64) and Debian 8 (3.16.0-4-amd64). So far, I could not reproduce a problem with 32-bit systems.
A patch for Opensim has been provided http://opensimulator.org/mantis/view.php?id=7900 (Crash due to setting Thread.name after thread start.) The patch has been successfully demonstrated on a number of system configuration. The crash condition returns when the patch is reverted. Conclude this issue is resolved.