How to reproduce:
1. Open the attached "CanvasRepro" project and "1" scene
2. Enter playmode
3. Go to Window --> Profiler and scroll down to UI section, click on UI section
4. Click on Canvas object in the Profiler

Result: Crash occurs on -

0x0000000141865093 (Unity) UI::CanvasManager::ProfilerRenderBatch
0x000000014152D7E5 (Unity) ProfilerProperty_CUSTOM_UISystemProfilerRender
0x000000003C249BBA (Mono JIT Code) (wrapper managed-to-native) UnityEditorInternal.ProfilerProperty:UISystemProfilerRender (int,int,int,bool)
0x000000003C249A79 (Mono JIT Code) [C:\buildslave\unity\build\Modules\Profiler\Editor\ProfilerWindow\UISystem\UISystemProfilerThumbnailService.cs:115] UnityEditor.UISystemProfilerRenderService:Generate (int,int,int,bool)
0x000000003C2498FF (Mono JIT Code) [C:\buildslave\unity\build\Modules\Profiler\Editor\ProfilerWindow\UISystem\UISystemProfilerThumbnailService.cs:127] UnityEditor.UISystemProfilerRenderService:GetThumbnail (int,int,int,bool)
0x000000003C234D87 (Mono JIT Code) [C:\buildslave\unity\build\Modules\Profiler\Editor\ProfilerWindow\UISystem\UISystemProfiler.cs:146]

Reproducible with - 2018.1.0b3, 2017.3.0p2, 2017.2.1p2, 2017.1.3f1, 2017.1.0a1

Note: If Canvas contains a child element, the crash does not happen, it only happens if Canvas does not contain any child GameObject