STEPS TO REPRODUCE
1. Create a new document (with:3508, height: 4960, Resolution: 300) with 32-bit float/channel
2. Create a new document (with:3508, height: 4960, Resolution: 300) with 16-bit float/channel.
3. Crash, if not, keep creating documents with different deeps.

OBSERVED RESULT
Doesn't crash without "Canvas acceleration" enabled or without "Use texture buffer" enabled.

Could be that the texture buffer capacity gets exhausted?

SOFTWARE VERSIONS
Version: 4.2.0-pre-alpha (git 0104ab7)
Qt
  Version (compiled): 5.9.3
  Version (loaded): 5.9.3

OS Information
  Build ABI: x86_64-little_endian-llp64
  Build CPU: x86_64
  CPU: x86_64
  Kernel Type: winnt
  Kernel Version: 10.0.10586

ADDITIONAL INFORMATION
OpenGL Info 
  Vendor:  Intel 
  Renderer:  "Intel(R) HD Graphics 4400" 
  Version:  "3.0.0 - Build 10.18.15.4248" 
  Shading language:  1.30 - Build 10.18.15.4248 
  Requested format:  QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::SwapBehavior(DoubleBuffer), swapInterval 0, profile  QSurfaceFormat::OpenGLContextProfile(CompatibilityProfile)) 
  Current format:    QSurfaceFormat(version 3.0, options QFlags<QSurfaceFormat::FormatOption>(DeprecatedFunctions), depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8, alphaBufferSize 8, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat::SwapBehavior(DoubleBuffer), swapInterval 1, profile  QSurfaceFormat::OpenGLContextProfile(NoProfile)) 
     Version: 3.0
     Supports deprecated functions true 
     is OpenGL ES: false 

QPA OpenGL Detection Info 
  supportsDesktopGL: true 
  supportsAngleD3D11: true 
  isQtPreferAngle: false 
  overridePreferAngle: true 

Internal Memory aprox. 4148MB (according to dxdiag)

Using Direct3D 11 via ANGLE (Auto selected by krita)


Probably related to https://bugs.kde.org/show_bug.cgi?id=393509