https://bugs.freedesktop.org/show_bug.cgi?id=102009
--- Comment #8 from Jan Vesely jan.vesely@rutgers.edu --- (In reply to Markus from comment #7)
I tried to obtain debug information from Mesa but was unable to do so (i.e. starting Blender with `MESA_DEBUG=context CYCLES_OPENCL_SPLIT_KERNEL_TEST=1 ./blender` did not generate any visible debug information).
What I did instead, is run Blender via gdb which then gave the attached stack trace at the time of crash. Looking at the trace, it appears like the crash is inside LLVM.
What is the best way to debug this further?
P.S.: As I just updated to Ubuntu 17.10 (Beta 2), I've also attached new glxinfo and clinfo output.
you can use CLOVER_DEBUG=clc,llvm,native CLOVER_DEBUG_FILE=blender to force clover to dump compiled CL programs (it should produce several dump files for .clc .ll .asm). Make sure the kernels are compiled and not loaded fomr ~/.cache/cycles/kernels
From there you can run and debug LLVM on the command line.
Note that I have been unable to reproduce this. blender-2.79 on OpenCL 1.1 Mesa 17.4.0-devel (git-138adc72e7) AMD Radeon R7 Graphics (CARRIZO / DRM 3.18.0 / 4.11.0-ROC-SC, LLVM 5.0.1) AMD Radeon (TM) R7 M340 (ICELAND / DRM 3.18.0 / 4.11.0-ROC-SC, LLVM 5.0.1)
instead it hits MAX_GLOBAL_BUFFERS assertion in radeonsi pipe driver. bumping the limit renders a picture albeit much different from CPU rendering