Okay -thx for the info and let's hope the vulcan architecture will do any good in the future for/with AMD. At the moment their catalyst driver support for linux really sucks.

For others:
At the moment you can't use catalyst on ubuntu kernel 4.2 which is shipped with 15.10
http://www.phoronix.com/scan.php?page=news_item&px=Ubuntu-15.10-4.2-Cat-Not-Ready

Solution for running Catalyst - stay with 14.04.2 LTS or install ppa 4.1 kernel.
You can also try to compile fglrx with gcc-4.9 instead of gcc-5.0 to avoid crashes on kernel 4.2...
http://ati.cchtml.com/show_bug.cgi?id=1189

I've got the same problem:

Linux Distribution: Ubuntu 15.10
Kernel Version: 4.2.0-16-generic #19-Ubuntu SMP Thu Oct 8 15:35:06 UTC 2015

Hardware Info:
Machine Type To Be Filled By O.E.M. To Be Filled By O.E.M. To Be Filled By O.E.M.
CPU Type AuthenticAMD x86_64
CPU Info AMD A8-7600 Radeon R7, 10 Compute Cores 4C+6G
CPU Speed 3100 MHz
CPU Physical Cores 4
CPU Logical Cores 4
Physical Memory 14355156 KiB
Virtual Memory 16601084 KiB
[...]
[thread 0000000f][E][723834]: Program from shader GL_FRAGMENT_SHADER with length 20611 and CRC 0xae61bc1c has not been successfully linked. Program info log:
error: Too many fragment shader texture samplers

OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD KAVERI (DRM 2.43.0, LLVM 3.8.0)
OpenGL core profile version string: 4.1 (Core Profile) Mesa 11.1.0-devel (padoka
PPA)

I also included my crash dump file 57ddd331-1ca5-fbe9-208791b9-1ae8f82a.dmp (zipped)

I tried with different kernel versions (4.3, 4.2...) and hope that it's not an AMD problem.

The VP port is running very smooth with the catalyst driver so far. One thing I observed which is crucial for running the system on linux to avoid other "mysterious" crashes. The /tmp partition should have at least 2 GB of free space. After some time the game uses up to 1.5 GB tmp files and will crash if you run out space...