Bug Crashes working with Unity UI

Hello,

It seems that since upgrading to 2021.3.20f1 I've been having lots of crashes while working with canvases. So far 3 in as many hours.

For obvious reasons I can't share the project or setup, but here'ss what the log contains every time. It always happens when I try doing something "normal" in the inspector - change rect transform position, change an image component's colour, etc. No obvious action triggers it, the only common thing has been working in a Canvas prefab.

Is this a known issue? Is anyone else seeing this?

Code (CSharp):

1. Registering precompiled user dll's ...
2. Registered in 0.007728 seconds.
3. Start importing Assets/Art/UI/image.png using Guid(dcc959033be351840b5b06cf14b9cd59) Importer(-1,00000000000000000000000000000000)  -> (artifact id: '845c520b43a6dcba0d8c72d775b3c035') in 0.016611 seconds
4. Refreshing native plugins compatible for Editor in 1.34 ms, found 1 plugins.
5. Preloading 0 native plugins for Editor in 0.00 ms.
6. Asset Pipeline Refresh: Total: 0.143 seconds - Initiated by StopAssetImportingV2(NoUpdateAssetOptions)
7. [Worker2] Start importing Assets/Art/UI/image.png using Guid(dcc959033be351840b5b06cf14b9cd59) Importer(815301076,1909f56bfc062723c751e8b465ee728b)
8. [Worker2]  -> (artifact id: 'fc990abc8ba88f79eb7d1b9bd0bc6622') in 0.009479 seconds
9. <RI> Initialized touch support.
10.  
11. Dereferencing NULL PPtr!
12.  
13. =================================================================
14.    Native Crash Reporting
15. =================================================================
16. Got a UNKNOWN while executing native code. This usually indicates
17. a fatal error in the mono runtime or one of the native libraries
18. used by your application.
19. =================================================================
20.  
21. =================================================================
22.    Managed Stacktrace:
23. =================================================================
24. =================================================================
25. Received signal SIGSEGV
26. Obtained 10 stack frames
27. 0x00007ff6a0359423 (Unity) GUIView::ProcessInputEventFromAPI
28. 0x00007ff6a03592f8 (Unity) GUIView::ProcessInputEvent
29. 0x00007ff6a08a381e (Unity) GUIView::DoPaint
30. 0x00007ff6a08acb5d (Unity) GUIView::RepaintAll
31. 0x00007ff6a042abd3 (Unity) Application::TickTimer
32. 0x00007ff6a087ff2a (Unity) MainMessageLoop
33. 0x00007ff6a08847fb (Unity) WinMain
34. 0x00007ff6a1c4d0ee (Unity) __scrt_common_main_seh
35. 0x00007ffc8d5f7614 (KERNEL32) BaseThreadInitThunk
36. 0x00007ffc8e6c26a1 (ntdll) RtlUserThreadStart

 

Hey! Me and another user have had the same crash - same unity version, on Windows 7 for them, and 10 for me.

Case 1

The user was just editing a material/tweaking colors/tweaking an image texture, but no prefabs were open.

Code (CSharp):

1.  
2. Obtained 10 stack frames
3. 0x00007ff6a3f69423 (Unity) GUIView::processInputEventFromAPI
4. 0x00007ff6a3f692f8 (Unity) GUIView::processInputEvent
5. 0x00007ff6a44b381e (Unity) GUIView::DoPaint
6. 0x00007ff6a44bcb5d (Unity) GUIView::RepaintAll
7. 0x00007ff6a403abd3 (Unity) Application::TickTimer
8. 0x00007ff6a448ff2a (Unity) MainMessageLoop
9. 0x00007ff6a44947fb (Unity) WinMain
10. 0x00007ff6a585d0ee (Unity) __scrt_common_main_seh
11. 0x00007fff43357614 (KERNEL32) BaseThreadInitThunk
12. 0x00007fff43c626a1 (ntdll) RtlUserThreadStart
13.  

Case 2
Bizarrely, I myself - on an earlier version of 2021.3 - had a similar crash with overlapping stack frames, mentioned here:
https://forum.unity.com/threads/better-ui.453808/page-9#post-8868714 . It's impossible to reproduce, and for me, mainly started happening when resizing the game view by dragging the window panes, or exiting play mode.
(The crash has nothing to do with BetterUI, I think.)

I have a two-monitor setup with unity windows on both. I also have a custom editorwindow I use for stuff but it doesn't throw errors, only rarely warnings about 'pushing more GUI clips than you are popping'. Both me and the other user usually have that window open.


Case 3
I would have crashes when unsetting/setting a physic material on an object, and using the undo key. This was a few weeks ago and hasn't happened since



Other

Unfortunately it seems random for us as well. My crashes stopped entirely after restarting my computer, the other user can't trigger it...

 

Maybe we can list non-traditional things about our setups that we might have in common:

1. We have two editor windows we make that have grid selections and some dropdowns, for placing prefabs
2. That tool also creates a lot of meshes in the undo stack
3. Our scene views sometimes have postprocessing applied (through URP)
4. I often have two scenes open, one with the canvas UI

 

for me, Unity 2021.3.19f1, it happens when I interact with an IMGUI EditorWiundow that opens in ShowAsDropDown() - I can't replicate a scenario but opening & closing this window while interacting with other UI components reproduces it after 15s.

the log is almost identical:

Code (CSharp):

1.  
2. ...
3. <RI> Initialized touch support.
4. Dereferencing NULL PPtr!
5. Received signal SIGSEGV
6. Obtained 9 stack frames
7. 0x00007ff6731c8a2a (Unity) GUIView::ProcessInputEvent
8. 0x00007ff673712f6e (Unity) GUIView::DoPaint
9. 0x00007ff67371c29d (Unity) GUIView::RepaintAll
10. 0x00007ff67329a313 (Unity) Application::TickTimer
11. 0x00007ff6736ef67a (Unity) MainMessageLoop
12. 0x00007ff6736f3f4b (Unity) WinMain
13. 0x00007ff674abb05e (Unity) __scrt_common_main_seh
14. 0x00007ffb2720269d (KERNEL32) BaseThreadInitThunk
15. 0x00007ffb27f0a9f8 (ntdll) RtlUserThreadStart
16.  
17.  

 

Getting this also. Extremely infuriating. Here is my crash log:

Code (csharp):

1.  
2. Dereferencing NULL PPtr!
3.  
4. =================================================================
5.     Native Crash Reporting
6. =================================================================
7. Got a UNKNOWN while executing native code. This usually indicates
8. a fatal error in the mono runtime or one of the native libraries
9. used by your application.
10. =================================================================
11.  
12. =================================================================
13.     Managed Stacktrace:
14. =================================================================
15. =================================================================
16. Received signal SIGSEGV
17. Obtained 9 stack frames
18. 0x00007ff6d9ce3d4a (Unity) GUIView::ProcessInputEvent
19. 0x00007ff6da22de4e (Unity) GUIView::DoPaint
20. 0x00007ff6da2370fd (Unity) GUIView::RepaintAll
21. 0x00007ff6d9db5603 (Unity) Application::TickTimer
22. 0x00007ff6da20aa1a (Unity) MainMessageLoop
23. 0x00007ff6da20f2eb (Unity) WinMain
24. 0x00007ff6db5c484e (Unity) __scrt_common_main_seh
25. 0x00007ffa61227034 (KERNEL32) BaseThreadInitThunk
26. 0x00007ffa617426a1 (ntdll) RtlUserThreadStart
27.  

 

I found this issue which is related. There is also a suggested fix in the comments: https://issuetracker.unity3d.com/is...orwindow-from-a-genericmenu-in-a-popup-window