Get NullReferenceException when running kestrel for a while

[cnblogs-dudu]

# dnx . kestrel
Started

Unhandled Exception: System.NullReferenceException: 
Object reference not set to an instance of an object.
at Microsoft.AspNet.Server.Kestrel.Networking.UvShutdownReq.UvShutdownCb(IntPtr ptr, Int32 status)

# dnx . kestrel
Started

[Tragetaschen]

#63

[shhsu]

I have actually gotten a similar issue during perf test, most of the time I get the NRE as above but sometimes I get this instead

Unhandled Exception: System.InvalidCastException: Unable to cast object of type 'ThisWriteReq' to type 'Microsoft.AspNet.Server.Kestrel.Networking.UvShutdownReq'.
at Microsoft.AspNet.Server.Kestrel.Networking.UvMemory.FromIntPtr[THandle](IntPtr handle)
at Microsoft.AspNet.Server.Kestrel.Networking.UvShutdownReq.UvShutdownCb(IntPtr ptr, Int32 status)

[sajayantony]

/cc @davidfowl do you guys have someone fixing this already. This is quite a bad blocking issue. @shhsu Do you have a potential fix for this?

[lodejard]

It sounds like the period of time that the async shutdown is "active" needs to be guarded by a gchandle as well. Same as the uvwritereq - handle created when operation begins and freed in the callback.

[shhsu]

The reproduction of this problem is simple.

• Build and run HelloMvc app with coreclr on linux (I used Ubuntu)
• Hit the index page with some load test (I used WCat)
  Kestrel should crash pretty fast (10~20 seconds)

Note: I seem to be getting similar trouble with Kestrel on coreclr on Windows as well. After hitting HelloMvc on Kestrel on Windows the dnx process would become unresponsive. I will be debugging it.