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AssemblyLoadContext crash when collectible assembly use XmlSerializer #1388

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#58932
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AssemblyLoadContext crash when collectible assembly use XmlSerializer#1388
#58932
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StephenMolloy
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area-Serialization
Milestone
 
6.0.0
@uffebjorklund

Description

@uffebjorklund
uffebjorklund
opened on Sep 24, 2019

[EDIT]
Investigation of this issue is complete and has resulted in 5 additional issues being opened.
See this comment below for links to each of those issues.

We will keep this issue open and update it as those other issues are fixed.
Please add any additional comments to those issues.

When creating a collectible AssemblyLoadContext and then use System.Xml.Serialization.XmlSerializer inside of a collectible assembly you will get a crash.

I have a repro project: https://github.com/uffebjorklund/AssemblyLoadContextBug

Have tried a few different things

  • If creating the ALC as collectible = false there is no crash
  • If the XmlSerializer code is removed from the collectible assembly there is no crash
  • The crash will occur regardless of using netstandard2.0 or netstandard2.1 on the collectible assembly

Exception

A non-collectible assembly may not reference a collectible assembly

Stacktrace

at System.Reflection.Emit.ModuleBuilder.GetTypeRef(QCallModule module, String strFullName, QCallModule refedModule, String strRefedModuleFileName, Int32 tkResolution)
at System.Reflection.Emit.ModuleBuilder.GetTypeRefNested(Type type, Module refedModule, String strRefedModuleFileName)
at System.Reflection.Emit.ModuleBuilder.GetTypeTokenWorkerNoLock(Type type, Boolean getGenericDefinition)
at System.Reflection.Emit.ModuleBuilder.GetTypeTokenInternal(Type type, Boolean getGenericDefinition)
at System.Reflection.Emit.ILGenerator.Emit(OpCode opcode, Type cls)
at System.Xml.Serialization.CodeGenerator.Castclass(Type target)
at System.Xml.Serialization.CodeGenerator.InternalConvert(Type source, Type target, Boolean isAddress)
at System.Xml.Serialization.SourceInfo.InternalLoad(Type elementType, Boolean asAddress)
at System.Xml.Serialization.XmlSerializationWriterILGen.WriteElement(SourceInfo source, ElementAccessor element, String arrayName, Boolean writeAccessor)
at System.Xml.Serialization.XmlSerializationWriterILGen.WriteElements(SourceInfo source, String enumSource, ElementAccessor[] elements, TextAccessor text, ChoiceIdentifierAccessor choice, String arrayName, Boolean writeAccessors, Boolean isNullable)
at System.Xml.Serialization.XmlSerializationWriterILGen.WriteMember(SourceInfo source, String choiceSource, ElementAccessor[] elements, TextAccessor text, ChoiceIdentifierAccessor choice, TypeDesc memberTypeDesc, Boolean writeAccessors)
at System.Xml.Serialization.XmlSerializationWriterILGen.GenerateTypeElement(XmlTypeMapping xmlTypeMapping)
at System.Xml.Serialization.XmlSerializationWriterILGen.GenerateElement(XmlMapping xmlMapping)
at System.Xml.Serialization.TempAssembly.GenerateRefEmitAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace)
at System.Xml.Serialization.TempAssembly..ctor(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, String location)
at System.Xml.Serialization.XmlSerializer.GenerateTempAssembly(XmlMapping xmlMapping, Type type, String defaultNamespace, String location)
at System.Xml.Serialization.XmlSerializer..ctor(Type type, String defaultNamespace)

dotnet --info

.NET Core SDK (reflecting any global.json):
 Version:   3.0.100
 Commit:    04339c3a26

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.13
 OS Platform: Darwin
 RID:         osx.10.13-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.0.100/

Host (useful for support):
  Version: 3.0.0
  Commit:  7d57652f33

.NET Core SDKs installed:
  2.1.301 [/usr/local/share/dotnet/sdk]
  2.1.302 [/usr/local/share/dotnet/sdk]
  2.1.400 [/usr/local/share/dotnet/sdk]
  2.1.401 [/usr/local/share/dotnet/sdk]
  2.1.403 [/usr/local/share/dotnet/sdk]
  2.1.500 [/usr/local/share/dotnet/sdk]
  2.2.100-preview3-009430 [/usr/local/share/dotnet/sdk]
  2.2.101 [/usr/local/share/dotnet/sdk]
  2.2.102 [/usr/local/share/dotnet/sdk]
  2.2.103 [/usr/local/share/dotnet/sdk]
  2.2.105 [/usr/local/share/dotnet/sdk]
  2.2.106 [/usr/local/share/dotnet/sdk]
  2.2.203 [/usr/local/share/dotnet/sdk]
  2.2.300 [/usr/local/share/dotnet/sdk]
  3.0.100-alpha1-009708 [/usr/local/share/dotnet/sdk]
  3.0.100-preview-010184 [/usr/local/share/dotnet/sdk]
  3.0.100-preview3-010431 [/usr/local/share/dotnet/sdk]
  3.0.100-preview8-013656 [/usr/local/share/dotnet/sdk]
  3.0.100-preview9-014004 [/usr/local/share/dotnet/sdk]
  3.0.100 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.0-preview3-35497 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 3.0.0-alpha1-10062 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.0-preview3-35497 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.3 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-alpha1-10062 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview-19075-0444 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview3-19153-02 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview8.19405.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview9.19424.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.0-preview3-27014-02 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.3 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.4 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview-27324-5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview1-27029-03 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview3-27503-5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview9-19423-09 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Activity

jkotas
transferred this issue fromdotnet/coreclron Sep 24, 2019
csalat

csalat commented on Oct 4, 2019

@csalat
csalat
on Oct 4, 2019

Hello,

Is any update on this?

Thanks,
Csaba

StephenBonikowsky

StephenBonikowsky commented on Nov 12, 2019

@StephenBonikowsky
StephenBonikowsky
on Nov 12, 2019
Member

@uffebjorklund Thanks for reporting this, sorry for the slow response. It looks like all the information we need to do further investigation is here. We will look into it.

StephenBonikowsky
assigned
StephenBonikowsky
and
mconnew
and unassigned
StephenBonikowsky
on Nov 12, 2019
mconnew

mconnew commented on Nov 22, 2019

@mconnew
mconnew
on Nov 22, 2019
Member

I did a bit of digging in to this and I believe that the problem is due to XmlSerializer creating a dynamic assembly in the default load context which makes the dynamic assembly non-collectible. When we call ILGenerator.Emit(OpCodes.Castclass, type) with a type which is a collectible assembly, we get an exception. I did some digging around the api's and I can't see a way to specify the AssemblyLoadContext to generate a dynamic assembly into.
@sdmaclea, is this scenario supported? If so, can you point me to the api's to create a dynamic assembly in a specific AssemblyLoadContext?

sdmaclea

sdmaclea commented on Nov 23, 2019

@sdmaclea
sdmaclea
on Nov 23, 2019
Contributor

@sdmaclea, is this scenario supported? If so, can you point me to the api's to create a dynamic assembly in a specific AssemblyLoadContext?

@mconnew I think this was a feature we missed in 3.0. There is an API proposal to close this gap dotnet/corefx#38426

/cc @vitek-karas @elinor-fung @jeffschwMSFT

curia-damiano

curia-damiano commented on Nov 23, 2019

@curia-damiano
curia-damiano
on Nov 23, 2019

Hi,
I share the same supposition, that it can be because of the dynamic generated assemblies.
But: I have tried using the XmlSerializerGenerator, with the idea that it wouldn't generated dynamic assemblies anymore.
But still I can't make it to work, see attached solution.
Do I miss anything?!?
Test_ALC with XmlSerializerGenerator.zip

curia-damiano

curia-damiano commented on Nov 23, 2019

@curia-damiano
curia-damiano
on Nov 23, 2019

Btw this was my first project with the issue, without the XmlSerializerGenerator
Test_ALC.zip

vitek-karas

vitek-karas commented on Nov 24, 2019

@vitek-karas
vitek-karas
on Nov 24, 2019
Member

@curia-damiano How do you generate the serialization code? I tried to turning it on via VS on the CL.Implementation.Problem assembly and that failed (which is probably an issue on its own, but not directly related to this issue).

Also - I noticed that your "plugins" are built as netstandard2.0 - this is not recommended as SDK will not always produce the right assets. Ideally plugins should not target a standard but a specific framework - for example netcoreapp3.1 or so.

curia-damiano

curia-damiano commented on Nov 25, 2019

@curia-damiano
curia-damiano
on Nov 25, 2019

Hi,
I have a ItemGroup in the project that "should" invoke the generation of the serialization code during build time. I haven't found any additional documentation saying I should do something more.
FYI I have used VS 2019 Preview (16.4.0 Preview 5 or 6).

vitek-karas

vitek-karas commented on Nov 25, 2019

@vitek-karas
vitek-karas
on Nov 25, 2019
Member

I tried again - Release build this time - and I spotted this in the output of the build:

3>Method 'System.Xml.Serialization.XmlSerializer.GenerateSerializer' was not found. This is likely because you are using an older version of the framework. Please update to .NET Core v2.1 or later.
3>Sgen utility failed to pregenerate serialization code for E:\AppModel\repro\Test_ALC\CL.Implementation.Problem\obj\Release\netstandard2.0\CL.Implementation.Problem.dll.

@StephenMolloy for the XML serializer specific portions of this question, like the above failure of sgen.

mconnew

mconnew commented on Nov 25, 2019

@mconnew
mconnew
on Nov 25, 2019
Member

@curia-damiano, I haven't tried running your code yet but I can see a problem in Test_ALC with XmlSerializerGenerator.zip. This is the problem code:

	var assembly = TLC.LoadFromAssemblyPath(dllPath);
	labelUnloaded.Text = "Loaded";
	var type = assembly.GetType("CL.Implementation.Easy.Multiplier");
	var constructor = type.GetConstructor(new Type[] { });
	ICompute compute = (ICompute)constructor.Invoke(new object[] { });

When using a different AssemblyLoadContext, the same type in the same assembly is a different runtime type. So this means the ICompute interface that CL.Implementation.Easy.Multiplier implements is a different runtime type that the same interface in the default load context. So the cast on the last line will fail.

mconnew

mconnew commented on Nov 25, 2019

@mconnew
mconnew
on Nov 25, 2019
Member

@sdmaclea, in this comment it says it uses the callers AssemblyLoadContext. You can see here that we do use AssemblyBuilder.DefineDynamicAssembly so I would expect the dynamically created assembly to use the custom AssemblyLoadContext. Is the problem that we pass AssemblyBuilderAccess.Run instead of AssemblyBuilderAccess.RunAndCollect? What's stopping the dynamically generated assembly from being created in the correct context? Also, is this going to be a problem for DispatchProxy too?

59 remaining items

jkotas

jkotas commented on Mar 5, 2021

@jkotas
jkotas
on Mar 5, 2021
Member

#48072 is not in .NET 6 Preview 1. It will be in Preview 2.

bzuidgeest
mentioned this on Apr 21, 2021
StephenMolloy
assigned
HongGit
and
StephenMolloy
and unassigned
mconnew
and
HongGit
on Jun 21, 2021
StephenMolloy
removed
trackingThis issue is tracking the completion of other related issues.
on Jul 27, 2021
StephenMolloy
mentioned this on Sep 10, 2021
ghost added
in-prThere is an active PR which will close this issue when it is merged
on Sep 10, 2021
StephenMolloy
closed this as completedin #58932on Nov 5, 2021
ghost removed
in-prThere is an active PR which will close this issue when it is merged
on Nov 5, 2021
chswin

chswin commented on Dec 2, 2021

@chswin
chswin
on Dec 2, 2021

This is not fixed in .net 6...

StephenMolloy

StephenMolloy commented on Dec 2, 2021

@StephenMolloy
StephenMolloy
on Dec 2, 2021
Member

@chswin, this has been fixed in 7.0... and the issue unfortunately got closed when that PR was pushed through. We are trying to get approval to bring this back to 6.0, so I do expect it to show up in a servicing release. But you are correct, it is not yet fixed in .Net 6.

ghost locked as resolved and limited conversation to collaborators on Jan 2, 2022
StephenMolloy

StephenMolloy commented on Jan 14, 2022

@StephenMolloy
StephenMolloy
on Jan 14, 2022
Member

The PR that brings this into the 6.0 servicing branch is #61266.

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      AssemblyLoadContext crash when collectible assembly use XmlSerializer · Issue #1388 · dotnet/runtime