Fatal Execution Engine Error con Framework a 64 bit

Recentemente ho lavorato ad un paio di casi relativi a questo errore, spero con questo post di risparmiare un po’ di stress e mal di testa a qualcun’altro.

Il problema si manifesta solamente con il Framework a 64 bit (la stessa applicazione eseguita con il Framework a 32 bit funziona correttamente): il processo termina maniera random e nell’event log vengono loggati messaggi simili al seguente:

Event Type:      Error
Event Source:   .NET Runtime
Date:                12-02-2009 10:58:36
User:                N/A
Computer:       <computername>
Description: .NET Runtime version 2.0.50727.3082 - Fatal Execution Engine Error (000006427F8A5DC8) (80131506)

Catturando un crash dump del processo, lo stack del thread “problematico” è questo:

 0:025> kpL1000
Child-SP          RetAddr           Call Site
00000000`0643e350 00000642`78acb013 mscorwks!COMCryptography::_DecryptData+0x329
00000000`0643e590 00000642`801f4b87 mscorlib_ni!System.Security.Cryptography.CryptoAPITransform.TransformFinalBlock(<HRESULT 0x80004001>)+0x123
00000000`0643e620 00000642`801f25c7 CryptoSample!MyCryptoClass.Decrypt(<HRESULT 0x80004001>)+0xf7
00000000`0643e960 00000642`bc8e449b System_Web_ni!System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute(<HRESULT 0x80004001>)+0x257
00000000`0643ea10 00000642`bc8f2215 System_Web_ni!System.Web.HttpApplication.ExecuteStep(<HRESULT 0x80004001>)+0xab
00000000`0643eab0 00000642`bc8e3553 System_Web_ni!System.Web.HttpApplication+ApplicationStepManager.ResumeSteps(<HRESULT 0x80004001>)+0x1a5
00000000`0643eb60 00000642`bc8e7874 System_Web_ni!System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(<HRESULT 0x80004001>)+0xd3
00000000`0643ebc0 00000642`bc8e745c System_Web_ni!System.Web.HttpRuntime.ProcessRequestInternal(<HRESULT 0x80004001>)+0x1c4
00000000`0643ec50 00000642`bc8e608c System_Web_ni!System.Web.HttpRuntime.ProcessRequestNoDemand(<HRESULT 0x80004001>)+0x7c
00000000`0643ec90 00000642`7f602322 System_Web_ni!System.Web.Hosting.ISAPIRuntime.ProcessRequest(<HRESULT 0x80004001>)+0x18c
00000000`0643edc0 00000642`7f503bb3 mscorwks!CallDescrWorker+0x82
00000000`0643ee20 00000642`7f5251f8 mscorwks!CallDescrWorkerWithHandler+0xd3
00000000`0643eec0 00000642`7f525563 mscorwks!ForwardCallToManagedMethod+0x160
00000000`0643ef60 00000642`7f544738 mscorwks!COMToCLRWorkerBody+0x35b
00000000`0643f1c0 00000642`7f50c8ae mscorwks!COMToCLRWorkerDebuggerWrapper+0x50
00000000`0643f230 00000642`7f60249e mscorwks!COMToCLRWorker+0x366
00000000`0643f520 00000642`fff58293 mscorwks!GenericComCallStub+0x5e
00000000`0643f5d0 00000642`fff58633 webengine!HttpCompletion::ProcessRequestInManagedCode+0x2a3
00000000`0643fa80 00000642`fff9abf4 webengine!HttpCompletion::ProcessCompletion+0x63
00000000`0643fac0 00000642`7f48dc77 webengine!CorThreadPoolWorkitemCallback+0x24
00000000`0643faf0 00000642`7f4a289a mscorwks!UnManagedPerAppDomainTPCount::DispatchWorkItem+0x157
00000000`0643fb90 00000642`7f41f0ac mscorwks!ThreadpoolMgr::WorkerThreadStart+0x1ba
00000000`0643fc30 00000000`77d6b6da mscorwks!Thread::intermediateThreadProc+0x78
00000000`0643ff80 00000000`00000000 kernel32!BaseThreadStart+0x3a





0:025> !clrstack
OS Thread Id: 0x1258 (25)
Child-SP         RetAddr          Call Site
000000000643e590 00000642801f4b87 System.Security.Cryptography.CryptoAPITransform.TransformFinalBlock(Byte[], Int32, Int32)
000000000643e620 00000642801f25c7 MyCryptoClass.Decrypt(System.String, System.String, Boolean)
000000000643e960 00000642bc8e449b System.Web.HttpApplication+CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
000000000643ea10 00000642bc8f2215 System.Web.HttpApplication.ExecuteStep(IExecutionStep, Boolean ByRef)
000000000643eab0 00000642bc8e3553 System.Web.HttpApplication+ApplicationStepManager.ResumeSteps(System.Exception)
000000000643eb60 00000642bc8e7874 System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(System.Web.HttpContext, System.AsyncCallback, System.Object)
000000000643ebc0 00000642bc8e745c System.Web.HttpRuntime.ProcessRequestInternal(System.Web.HttpWorkerRequest)
000000000643ec50 00000642bc8e608c System.Web.HttpRuntime.ProcessRequestNoDemand(System.Web.HttpWorkerRequest)
000000000643ec90 000006427f602322 System.Web.Hosting.ISAPIRuntime.ProcessRequest(IntPtr, Int32)

Non voglio tediarvi con i dettagli (ma se siete interessati, lasciate pure un commento ), sostanzialmente si tratta di verificare se nel vostro codice utilizzate i metodi Convert.FromBase64String (o direttamente CryptoAPITransform.TransformFinalBlock): se lo fate, assicuratevi di non passare una stringa vuota come parametro da convertire. Ad esempio:

 Public Function Decrypt(ByVal Source As String) As String
    
    Dim byteArr As Byte() = System.Convert.FromBase64String(Source)
    
    [...]
    
End Function

dovrebbe essere modificato in:

 Public Function Decrypt(ByVal Source As String) As String
    'convert from Base64 to binary

    If Not IsNullOrEmpty(Source) Then
        Return String.Empty
    End If
    
    Dim byteArr As Byte() = System.Convert.FromBase64String(Source)
    
    [...]
    
End Function

Carlo Cardella
Senior Support Engineer
EMEA IIS and Web Developer Support