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NET 7: Calling GC.Collect() causes Access Violation exception (cx0000005) #79486
Description
Description
Calling GC.Collect() when having sufficiently large objects in LOH and using the Server Garbage Collection causes Access Violation exception (cx0000005) being thrown from coreclr.dll
CoreCLR Version: 7.0.22.51805
.NET Version: 7.0.0
Description: The process was terminated due to an unhandled exception.
Exception Info: exception code c0000005
We have seen this on Windows 10 Enterprise and on Windows Server 2016
Reproduction Steps
Code
open System
[<Struct>]
type T = {
A: DateTime
B: int
C: float
D: byte }
let data: T array = Array.zeroCreate 2_000_000_000
GC.Collect()
printfn "All OK"
Project file
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net7.0</TargetFramework>
<ServerGarbageCollection>true</ServerGarbageCollection>
</PropertyGroup>
<ItemGroup>
<Compile Include="Program.fs" />
</ItemGroup>
</Project>
Run this with dotnet run -c release
Changes that leads to program running OK
- Allocating with size
1_000_000_000 - Changing the order of
BandCin the struct
Expected behavior
The program writes All OK to the console.
Actual behavior
The program crashes and we see in the Event log that The process was terminated due to an unhandled exception with exception code c0000005
Regression?
We never saw this on NET 6, but it appeared immediately efter we upgraded to NET 7.
Known Workarounds
No response
Configuration
.NET version
CoreCLR Version: 7.0.22.51805
.NET Version: 7.0.0
OS
Edition Windows 10 Enterprise
Version 21H2
Installed on 03/10/2020
OS build 19044.2251
Experience Windows Feature Experience Pack 120.2212.4180.0
Architecture
x64
Other information
No response
Activity
deeprobin commentedon Dec 11, 2022
Cannot reproduce with Workstation-GC.
mrsharm commentedon Dec 12, 2022
Hi @nilekirk,
I am failing to repro this issue on my machine. I am getting Out of Memory Errors vs. an Access Violation when I set the heap hard limit to control the amount of memory allowed in an effort to replicate the conditions. Could you please provide me the amount of memory the machine you are using has? Also, could you provide a memory dump for this issue, as well?
Thanks in advance!
samme78 commentedon Dec 13, 2022
I can reproduce this, I get the same application error.
OS
Edition Windows 10 Pro
Version 21H2
Installed on 2021-09-22
OS build 19044.2251
Experience Windows Feature Experience Pack 120.2212.4180.0
Computer
Processor 11th Gen Intel(R) Core(TM) i9-11950H @ 2.60GHz 2.61 GHz
Installed RAM 64,0 GB (63,2 GB usable)
System type 64-bit operating system, x64-based processor
Resolution
If I change the size to
1_000_000_000or change the order of B and C in the struct the program works as expected and prints the "All OK".mrsharm commentedon Dec 14, 2022
Thanks, @samme78! We are able to consistently repro this issue and are working on diagnosing the cause to work on a fix. We appreciate you reporting this issue!