I've deployed an ASP.NET web application on a Linux (Debian) server running Apache 2.2 and mod_mono 1.9

It's working well, however Mono occasionally segfaults and uses the entire CPU which causes the website to stop working and display 'Service Temporarily Unavailable'

Killing mono fixes it, but obviously this isn't a good solution.

I tailed the system log after this happened and I saw the following error messages from the kernel:

Apr 20 01:49:37 charliesomerville kernel: [1596436.204158] mono[17909]: segfault at b645f671 ip b645f671 sp b4ffb604 error 4<6>mono[19047]: segfault at b645f66e ip b645f66e sp b4bf7604 error 4<6>mono[18017]: segfault at b645f66e ip b645f66e sp b52fe604 error 4<6>mono[19668]: segfault at b645f5e6 ip b645f5e6 sp b48f4604 error 4<6>mono[22565]: segfault at b645f674 ip b645f674 sp b45f1604 error 4<6>mono[17700]: segfault at b645f661 ip b645f661 sp b51fd604 error 4<6>mono[19596]: segfault at b645f5e6 ip b645f5e6 sp b49f5604 error 4
Apr 20 01:49:37 charliesomerville kernel: [1596436.208172] mono[23219]: segfault at b645f66e ip b645f66e sp b44f0604 error 4

At the end of Apache's error.log are the following errors:

[Tue Apr 20 03:10:23 2010] [error] (70014)End of file found: read_data failed
[Tue Apr 20 03:10:23 2010] [error] Command stream corrupted, last command was 1
[Tue Apr 20 03:10:23 2010] [error] Command stream corrupted, last command was 1
[Tue Apr 20 03:10:23 2010] [error] Command stream corrupted, last command was 1
System.ArgumentNullException: null key
Parameter name: key
  at System.Collections.Hashtable.get_Item (System.Object key) [0x00000]
  at System.Runtime.Serialization.SerializationCallbacks.GetSerializationCallbacks  (System.Type t) [0x00000]
  at System.Runtime.Serialization.ObjectManager.RaiseOnDeserializingEvent (System.Object obj) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObjectContent (System.IO.BinaryReader reader, System.Runtime.Serialization.Formatters.Binary.TypeMetadata  metadata, Int64 objectId, System.Object& objectInstance, System.Runtime.Serialization.SerializationInfo& info) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObjectInstance  (System.IO.BinaryReader reader, Boolean isRuntimeObject, Boolean hasTypeInfo, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObject (BinaryElement element, System.IO.BinaryReader reader, System.Int64& objectId, System.Object& value, System.Runtime.Serialization.SerializationInfo& info) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadNextObject (System.IO.BinaryReader reader) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.ObjectReader.ReadObjectGraph (System.IO.BinaryReader reader, Boolean readHeaders, System.Object& result, System.Runtime.Remoting.Messaging.Header[]& headers) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.NoCheckDeserialize (System.IO.Stream serializationStream, System.Runtime.Remoting.Messaging.HeaderHandler handler) [0x00000]
  at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize (System.IO.Stream serializationStream) [0x00000]
  at System.Runtime.Remoting.Channels.CADSerializer.DeserializeObject (System.IO.MemoryStream mem) [0x00000]
  at System.Runtime.Remoting.RemotingServices.GetDomainProxy (System.AppDomain domain) [0x00000]
  at System.AppDomain.CreateDomain (System.String friendlyName, System.Security.Policy.Evidence securityInfo, System.AppDomainSetup info) [0x00000]
  at System.Web.Hosting.ApplicationHost.CreateApplicationHost (System.Type hostType, System.String virtualDir, System.String physicalDir) [0x00000]
  at Mono.WebServer.VPathToHost.CreateHost (Mono.WebServer.ApplicationServer server, Mono.WebServer.WebSource webSource) [0x00000]
  at Mono.WebServer.ApplicationServer.GetApplicationForPath (System.String vhost, Int32 port, System.String path, Boolean defaultToRoot) [0x00000]
  at (wrapper remoting-invoke-with-check) Mono.WebServer.ApplicationServer:GetApplicationForPath (string,int,string,bool)
  at Mono.WebServer.ModMonoWorker.GetOrCreateApplication (System.String vhost, Int32 port, System.String filepath, System.String virt) [0x00000]
  at Mono.WebServer.ModMonoWorker.InnerRun (System.Object state) [0x00000]
  at Mono.WebServer.ModMonoWorker.Run (System.Object state) [0x00000]
[Tue Apr 20 03:10:26 2010] [error] (70014)End of file found: read_data failed
[Tue Apr 20 03:10:26 2010] [error] Command stream corrupted, last command was -1

Along with the above errors, Apache's error.log is packed with hundreds (if not thousands) of the following error:

 Maximum number (20) of concurrent mod_mono requests to /tmp/mod_mono_dashboard_default_2.lock reached. Droping request.

At the moment, I'm thinking there might be something wrong with configuration here (it's basically running on out-of-the-box config)