"Fatal error in gc: Too many heap sections"

Since 2018.3, we've been getting this error frequently while doing an allocation-intensive operation:



Admittedly, we allocate a lot of memory during that operation (~40MiB), but it was never an issue in previous versions of Unity.

Could something have changed under the hood in how GC is managed? Maybe in preparation for incremental GC? Is there any way to avoid this error?

 

Make that two people. It seems to occur whenever the application exceeds 3.5GB of CPU memory allocation. It's like Unity is running in 32-bit mode somehow. This is running in editor mode.

 

We also have this happening when we recompile or try to make a build. It always happens around compilation but the crash stack trace is always different. We can repro it with only script and assembly(.dll) assets in the project. This was after we upgraded our project to 2018.3. We assumed it was something in our source that the compiler was having troubles compiling. We've had bugs like that before unfortunately. It takes a while to figure out what peice of code it was so we are just avoiding the upgrade for now. Though, I am not sure it is the same issue the OP is having.

 

Could you please submit a bug-report, as described in this document:
https://unity3d.com/unity/beta/guide-to-beta-testing#tab-3

After you submitted the report, you receive a confirmation email with a Case number. Please post this bug-report Case number here (in this thread) for Unity staff to pick up.

 

I can submit a bug report but I can't guarantee a 100% repro. It seems to depend on memory layout & usage prior to the intensive operation. Would it help more if I waited to get an actual crash from it so that the dump is included?

 

It probably does.

 

I just submitted a crash dump. Case 1104564.

 

I submitted a bug report on November 15th. The case number is 1101240. I attached several logs with crash stack traces in them. I cannot provide a repro project as it would currently require us to send our entire code base.

 

Do you use Vegetation Studio? I think someone with Vegetation Studio Pro has already submitted something. If not, I would try to get a test project. In my project it is reproducible in 5 or 6 clicks.

 

I just attached a very simple repro project to my fogbugz case. It just spams allocations in an update loop until it crashes. The issue isn't that it crashes, so much as _when_ it does. Which is just after about 4GB of allocations occurs. Then unrelated variables reset to zero, and other weird stuff happens. I used 2018.3.0b12 for this.

 

Thanks for following up. In our case, we are far from reaching even the 1GB threshold, we're still in the MBs, so I doubt the heap is actually running out of space.

 

For the benefit of others who are hitting an absolute allocation limit: I was able to work around this issue by using NativeArrays. Of course, you have to manually dispose the memory, but that's often acceptable.

 

that's a good news for the fix !
So I can deduce that you will release rc or maybe final soon ?
Even with all the warning in the poll feedback :/

 

Good news, let's hope is coming in 2018.3.0

 

Is it fixed ( regression has been fixed and we switched the limits back to what it was in 18.2.) in the 2018.3.0f1?

Thanks,

 

I got this today, on the latest build 2018.3.0f1. It looks like it might have something to do with dragging and dropping a script into a button event. But I am not 100 percent.

 

I had this issue on machines running 2018.3.0b2, and it seems fixed fixed on 2018.3.0f1.