Intermittent PolicyException:无法获取执行权限

Question

在ASP.NET应用程序中应用程序池回收后不久,我们间歇性地看到以下异常:

System.Configuration.ConfigurationErrorsException: Could not load file or assembly 'Microsoft.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Failed to grant permission to execute. (Exception from HRESULT: 0x80131418) ---> System.IO.FileLoadException: Could not load file or assembly 'Microsoft.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Failed to grant permission to execute. (Exception from HRESULT: 0x80131418)
File name: 'Microsoft.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' ---> System.Security.Policy.PolicyException: Execution permission cannot be acquired.
   at System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission)
   at System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission)
   at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)
   at System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.Load(String assemblyString)
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)

无法加载的特定DLL因事件而异,但始终是主程序集引用的DLL.

我们在Windows Server 2008上运行ASP.NET 3.5.这似乎分批发生,影响同一个应用程序池中的某些但不是所有站点.我们有大量网站都运行相同的代码.

一旦站点无法加载DLL,它就会抛出黄色死亡屏幕,直到下一个应用程序池回收.我们无法重现这种行为,并且这些网站在失败之前似乎一次可以工作数天或数周(以及许多App Pool回收).

有没有人见过类似的行为？

更新:

我们已经尝试通过设置几百个站点并编写脚本来重复发现故障,同时每隔几分钟回收一次App Pool,并且除了连续几天将服务器CPU连接起来之外无法完成其他任务. .

然后我们尝试使用ASP.NET制作和管理的DLL的副本来混乱(锁定其中一个DLL,更改文件权限)以重现类似的行为但不是同一个异常.

有没有人对如何调整安全策略以使其System.Security.Policy.PolicyException: Execution permission cannot be acquired.在加载特定DLL时抛出一个有任何想法？