System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-11-29 08:04, hash: rB13c820d87b62
Worked: -

Short description of error
Using a Sky Texture node for the world background results in a divide by zero in background_cdf (light.cpp), because cdf_total is zero.

Exact steps for others to reproduce the error

1. Start Blender with a debugger attached. Set a breakpoint on the line float cdf_total_inv = 1.0f / cdf_total; with the condition set to cdf_total == 0.0f.
2. Set the render engine to Cycles.
3. In the shader editor for the world, add a Sky Texture node and connect it to the Background node.
4. Set viewport shading to Rendered.

or

1. Start Blender with a debugger attached. Set a breakpoint on the line float cdf_total_inv = 1.0f / cdf_total; with the condition set to cdf_total == 0.0f.
2. Open attached file.
3. Set viewport shading to Rendered.