[2012-03-22 22:46:43] Started cgminer 2.3.1
[2012-03-22 22:46:43] Started cgminer 2.3.1
[2012-03-22 22:46:43] Probing for an alive pool
[2012-03-22 22:46:44] Long-polling activated for http://mining.eligius.st:8337/LP
Segmentation fault
root@ds-r:~/cgminer-2.3.1-2#
Running on debian squeeze, sdk 2.4, newer/ish fglrx
I get the same error from both a self built and the pre-built ubuntu binary.
I'm getting a similar segfault with 12.x fglrx if I use an SDK older than 2.6 (debian testing, though). The best solution I found was to remove the APP SDK completely, install the packages "opencl-headers", "amd-libopencl1" and "amd-opencl-icd" and run cgminer with "GPU_USE_SYNC_OBJECTS=1" set after re-compiling it. Alternatively, using fglrx 11.x was the only alternative I found.
But then, I compile cgminer myself and have never gotten the opencl version mismatch.