Asp.Net 5.0 RC1 Blazor - Assemblies loaded via AssemblyLoadContext.Default.LoadFromStream corrupt over time

[allderidge]

Description

In Asp.Net 5.0 RC1 WASM Blazor when an assembly is loaded via AssemblyLoadContext.Default.LoadFromStream it appears to corrupt over time resulting in various issues in reflection and directly accessing methods.

One form of Assembly corruption is reproduced in https://github.com/allderidge/BlazorBugReport_AssemblyCorruption . Additional stack traces have been included from the project where this issue was found.

The following steps caused the original issue:

• The application loads assemblies from its server via AssemblyLoadContext.Default.LoadFromStream
• DataContractSerialization involving the loaded assemblies is performed
• The application continues to initialise
• Various issues are triggered. Different issues are found by changing code that 'exercises' types found in the loaded assemblies either by construction, reflection or deserialisation.
• All code that generates the issue can be made to succeed dependent on ordering.

Example Stack 1

Uncaught (in promise) Error: System.Globalization.CultureNotFoundException: Culture is not supported. (Parameter 'name')
 � � is an invalid culture identifier.
   at System.Globalization.CultureInfo.GetCultureInfo(String name)
   at System.Reflection.AssemblyName.FillName(MonoAssemblyName* native, String codeBase, Boolean addVersion, Boolean addPublickey, Boolean defaultToken)
   at System.Reflection.AssemblyName.Create(IntPtr monoAssembly, String codeBase)
   at System.Reflection.RuntimeAssembly.GetName(Boolean copiedName)
   at System.Reflection.Assembly.GetName()
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.AssemblyKey..ctor(Assembly assembly)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.<>c__DisplayClass12_0.<GetRequiredLoadedAssembly>b__0(Assembly a)
   at System.Linq.Enumerable.TryGetLast[Assembly](IEnumerable`1 source, Func`2 predicate, Boolean& found)
   at System.Linq.Enumerable.LastOrDefault[Assembly](IEnumerable`1 source, Func`2 predicate)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.GetRequiredLoadedAssembly(AssemblyKey assemblyKey)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.ScanAssemblyForCallableMethods(AssemblyKey assemblyKey)
   at System.Collections.Concurrent.ConcurrentDictionary`2[[Microsoft.JSInterop.Infrastructure.DotNetDispatcher.AssemblyKey, Microsoft.JSInterop, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Collections.Generic.IReadOnlyDictionary`2[[System.String, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.ValueTuple`2[[System.Reflection.MethodInfo, System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Type[], System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Private.CoreLib, Version=5.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].GetOrAdd(AssemblyKey key, Func`2 valueFactory)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.GetCachedMethodInfo(AssemblyKey assemblyKey, String methodIdentifier)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.InvokeSynchronously(JSRuntime jsRuntime, DotNetInvocationInfo& callInfo, IDotNetObjectReference objectReference, String argsJson)
   at Microsoft.JSInterop.Infrastructure.DotNetDispatcher.BeginInvokeDotNet(JSRuntime jsRuntime, DotNetInvocationInfo invocationInfo, String argsJson)
    at Object.endInvokeDotNetFromJS (blazor.webassembly.js:1)
    at Object.invokeJSFromDotNet (blazor.webassembly.js:1)
    at Object.w [as invokeJSFromDotNet] (blazor.webassembly.js:1)
    at _mono_wasm_invoke_js_blazor (dotnet.5.0.0-rc.1.20451.14.js:1)
    at do_icall (<anonymous>:wasm-function[10583]:0x1944fd)
    at do_icall_wrapper (<anonymous>:wasm-function[3296]:0x79894)
    at interp_exec_method (<anonymous>:wasm-function[2147]:0x4442c)
    at interp_runtime_invoke (<anonymous>:wasm-function[7851]:0x12e8ab)
    at mono_jit_runtime_invoke (<anonymous>:wasm-function[7334]:0x11

The same exception is found in other code that calls Assembly.GetName().

Example Stack 2

System.BadImageFormatException: Invalid method header local vars signature token 0x  d4400f
	 File name: '_____ name removed ________'
	    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
	    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
	    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
	    at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
	    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
	    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
	    at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)

Example 4

System.BadImageFormatException: Method has zero rva
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 id, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)
    at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator reader, String name, String ns, Type declaredType, DataContract& dataContract)
    at System.Runtime.Serialization.XmlObjectSerializerReadContext.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
    at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, DataContract dataContract, String name, String ns)
    at System.Runtime.Serialization.DataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName, DataContractResolver dataContractResolver)
    at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)
    at System.Runtime.Serialization.DataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)```

Example 5

System.TypeLoadException: Could not resolve type with token 01000024 from typeref (expected class '__removed__' in assembly '__removed__, Version=1.0.0.0, Culture=neutral, PublicKeyToken=__removed__')

Further technical details

• ASP.NET Core version: 5.0.0-rc.1.20451.17
• Include the output of dotnet --info

dotnet --info
.NET SDK (reflecting any global.json):
 Version:   5.0.100-rc.1.20452.10
 Commit:    473d1b592e

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19041
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.100-rc.1.20452.10\

Host (useful for support):
  Version: 5.0.0-rc.1.20451.14
  Commit:  38017c3935

.NET SDKs installed:
  2.1.504 [C:\Program Files\dotnet\sdk]
  2.1.602 [C:\Program Files\dotnet\sdk]
  2.1.700-preview-009601 [C:\Program Files\dotnet\sdk]
  3.0.100-preview4-011223 [C:\Program Files\dotnet\sdk]
  3.1.103 [C:\Program Files\dotnet\sdk]
  3.1.200 [C:\Program Files\dotnet\sdk]
  3.1.300-preview-015048 [C:\Program Files\dotnet\sdk]
  3.1.302 [C:\Program Files\dotnet\sdk]
  3.1.402 [C:\Program Files\dotnet\sdk]
  5.0.100-preview.8.20417.9 [C:\Program Files\dotnet\sdk]
  5.0.100-rc.1.20452.10 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview4-19216-03 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0-preview.8.20414.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0-rc.1.20451.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview4-27615-11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0-preview.8.20407.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0-rc.1.20451.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview4-27613-28 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0-preview.8.20411.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0-rc.1.20452.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version
  Microsoft Visual Studio Enterprise 2019 Preview Version 16.8.0 Preview 3.0

Regression?

The previous code base on Blazor 3.1 didn't have these issues although it used Assassin.Load instead.

[lewing]

This looks like preview8 not rc1? Can you reproduce the issue with rc2?

[allderidge]

Sorry, I had the wrong terminal window to get the dotnet --info, I've updated it to have the correct machines output. The packages installed in the project are all 5.0.0-rc.1.20451.17. I'll give RC2 a go tomorrow.

Tagging subscribers to this area: @CoffeeFlux
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[allderidge]

The same issue exists with RC2.

The version information is now:

dotnet --info
.NET SDK (reflecting any global.json):
Version: 5.0.100-rc.2.20479.15
Commit: da7dfa8840

and the package versions are set to 5.0.0-rc.2.20475.17

[allderidge]

After some more investigation it appears that the main trigger for the stack traces given is using a DataContractSerializer followed by a GC.

The code in the repo https://github.com/allderidge/BlazorBugReport_AssemblyCorruption shows how deserialisation alters the name of the Assembly.

I think the DataContractSerializer code in this area is being changed as part of a fix for #42824, the changes to that code might help in that this issue might not be triggered.

The issue should never happen regardless of what the DataContractSerializer code does though; I.e. I would expect an Assembly to be immutable but its name as well as potentially the underlying IDL look like they are being mutated.

[lewing]

/cc @vargaz

[lambdageek]

We think the problem is that the runtime is keeping a pointer to arrAssembly (https://github.com/dotnet/runtime/blob/master/src/libraries/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs#L364) after the call to InternalLoad returns without pinning the array. So it gets collected by the GC and the runtime ends up pointing at junk. The call to mono_image_open_from_data_internal in mono_alc_load_raw_bytes (

runtime/src/mono/mono/metadata/appdomain.c

Line 2835 in 7601d44

MonoImage *image = mono_image_open_from_data_internal (alc, (char*)assembly_data, raw_assembly_len, FALSE, NULL, refonly, FALSE, NULL, NULL);

) is passing FALSE for need_copy so it ends up storing a pointer to the array data.

---

it doesn't seem wasm-specific. should fail on desktop Mono, too.

Tagging subscribers to this area: @CoffeeFlux
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