Crashing when performing certain operations inside of a VRayOSLTexture node

[shaneasimms]

V-Ray for Maya version: V-Ray Next for Maya, update 1 (v4.12.01.29159 from May 8 2019)
Maya version: 2019.3

I grabbed an OSL shader written for 3DS Max from here:
https://github.com/ADN-DevTech/3dsMa...iWindowBox.osl

But it causes V-Ray to crash. I have simplified it to demonstrate what I think is causing the crash:

shader jiWindowBox_Max
(
string filename = "missingcolor",
output color result = color(0.0),
)
{
color finalRGB;

color objI = transform("object", -I);
objI = -objI;

color objP = (color(u,v,0.5) * 2.0 - color(1.0)) * 0.5 + color(0.5);

color sections = step(0, objI);
color baseDepth = (objP-sections)/(-objI);

color baseDepthX = (objI*baseDepth[1] + objP + color(1.0));
color baseDepthY = (objI*baseDepth[0] + objP + color(1.0));

float horizU = baseDepthY[2] - 0.5;

// works
// finalRGB = color(horizU);

// doesn't work
finalRGB = color(clamp(horizU, 0.0, 1.0));

result = finalRGB;
}

In the above example, outputting "horizU" directly seems to give the correct result - but modifying it in any way appears to lead to a crash.

Has anyone seen this before?

[ikomitov]

Thanks for the report. I'll try to debug it.

Best regards,
Ivan

[shaneasimms]

Thanks for looking into it! Would be great to have a fix

[ikomitov]

I could not reproduce the crash (tried with all variants of the minimal shader and even with the original one) and I begin to suspect there is something to do with the backend codegen and the specific CPU. Any of the following would help to narrow down the issue:
1) Your exact CPU model. We've encountered similar crashes with Xeon Gold/SIlver/Platinum/Bronze in the past.
2) Any crash dumps and even plain V-Ray log files.
3) Any exported vrscenes would be helpful too.

Best regards,
Ivan

[shaneasimms]

Hey Ivan, sorry for the late response, and thanks so much for looking into this!

It is in fact running on an Intel Xeon Silver 4114 CPU @2.2GHz.
Unfortunately as it's a work thing getting any files to you is a little difficult, but I'll look into it.

Thanks, Shane

[ikomitov]

Thanks! That's already more than enough. I'll check if it is possible to backport any of the Xeon fixes back to 4.12.

Best regards,
Ivan

[shaneasimms]

Hey Ivan, just curious if there are any updates on this?

[ikomitov]

Hello Shane, I'm sorry about the delay. I'm working on porting the required patches to 4.12. I'll notify you, once I have a working test build for Maya 2019.

Best regards,
Ivan