Loading this assembly would produce a different grant set from other instances. (Exception from HRESULT: 0x80131401)

Describe the bug

• System.IO.FileLoadException occurred . The detail error message is below.

Exception: System.SystemException

Message: Failed to create AppDomain.

StackTrace:    at System.Web.Hosting.ApplicationManager.CreateAppDomainWithHostingEnvironment(String appId, IApplicationHost appHost, HostingEnvironmentParameters hostingParameters)
   at System.Web.Hosting.ApplicationManager.CreateAppDomainWithHostingEnvironmentAndReportErrors(String appId, IApplicationHost appHost, HostingEnvironmentParameters hostingParameters)
   at System.Web.Hosting.ApplicationManager.GetAppDomainWithHostingEnvironment(String appId, IApplicationHost appHost, HostingEnvironmentParameters hostingParameters)
   at System.Web.Hosting.ApplicationManager.CreateObjectInternal(String appId, Type type, IApplicationHost appHost, Boolean failIfExists, HostingEnvironmentParameters hostingParameters)
   at System.Web.Hosting.ProcessHost.StartApplication(String appId, String appPath, Object& runtimeInterface)

InnerException: System.IO.FileLoadException

Message: Loading this assembly would produce a different grant set from other instances. (Exception from HRESULT: 0x80131401)

StackTrace:    at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
   at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(Type type, Boolean nonPublic)
   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   at System.Activator.CreateInstance(String assemblyString, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, Evidence securityInfo, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(String assemblyName, String typeName)
   at System.AppDomain.CreateInstance(String assemblyName, String typeName)
   at System.AppDomain.CreateInstanceAndUnwrap(String assemblyName, String typeName)
   at System.AppDomain.CreateAppDomainManager()
   at System.AppDomain.Setup(Object arg)
   at System.AppDomain.nCreateDomain(String friendlyName, AppDomainSetup setup, Evidence providedSecurityInfo, Evidence creatorsSecurityInfo, IntPtr parentSecurityDescriptor)
   at System.AppDomain.InternalCreateDomain(String friendlyName, Evidence securityInfo, AppDomainSetup info)
   at System.AppDomain.CreateDomain(String friendlyName, Evidence securityInfo, AppDomainSetup info)
   at System.Web.Hosting.ApplicationManager.CreateAppDomainWithHostingEnvironment(String appId, IApplicationHost appHost, HostingEnvironmentParameters hostingParameters)

To Reproduce

1. install datadog-dotnet-apm-1.6.1-x64.msi
2. exec iisreset
3. access the application.

Runtime environment (please complete the following information):

• Instrumentation mode: automatic with msi installer
• 1.6.1
• OS: Windows Server 2016 R2
• CLR: NET Framework 4.7.2 / ASP.NET WebForms Application

Additional context

• I run 4 asp.net application in a website. 3 apps are nested. And only one app is failed to start by this error.

─ App1 (asp.net webforms) ok
        ├─App2(asp.net mvc) ok
        ├─App3(asp.net webapi) ok
        └─App4(asp.net webforms) System.IO.FileLoadException occurred!!

• What kind of situations is this exception happen?

[lucaspimentel]

Thanks, @prahutomo. Here is some documentation on the valid values for that setting.

Please keep in mind that forcing the loader optimization value to 1 (SingleDomain) is a workaround. The drawback is that multiple AppDomains in the same process will no longer be able share resources. For users with many applications running in the same IIS Application Pool, this setting can increase CPU and memory usage. Please use with caution!

Btw, we are actively working (https://github.com/DataDog/dd-trace-dotnet/pull/505) on loading our tracer assemblies in a different way that doesn’t interfere with the ability to share assemblies between AppDomains. This should eliminate the error without the need for this workaround.

[lucaspimentel]

We’ve done several changes over the last few months to alleviate this issue, if not solve it completely. There is also the workaround of changing the LoaderOptimization setting mentioned above.

We are closing this issue. Please re-open or create a new github issue if you encounter this again. Thanks.