1

We recently found that our application is throwing System.AccessViolationException when utilizing some third party library doing some unmanaged memory access. I will certainly try to work with the third party to get a fix from them, this post isn't for that though :).

I am hoping for some insights on how I can actually get this exception information into my logs. We're running Asp.net Core 5. We only found this error by enabling stdoutLogEnabled :https://learn.microsoft.com/en-us/aspnet/core/test/troubleshoot-azure-iis?view=aspnetcore-5.0#aspnet-core-module-stdout-log-iis. However, this isn't recommended for production environments. So my current question is, how can I actually capture the same log message stdoutLogEnabled=true was able to give us, by using some other logging provider, i.e. Log4Net.

I have the following in my appsettings:

"Logging": {
    "LogLevel": {
      "Default": "Trace",
    }
  },

And yet, when I run some unsafe code to to simulate the System.AccessViolationException I do not see if being logged in any of my log4net appenders.

I don't specifically have to get this working for log4net, that is just what we are using today. In general I would like to be able to capture this log using some advanced log provider so that it could potentially log somewhere other than a local file on the server.

Sample log output form the stdoutLogEnabled on the server

Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Repeat 2 times:
--------------------------------
   at   +.(IntPtr, System.String, Byte[], Int32, IntPtr ByRef, Int32 ByRef, IntPtr ByRef, System.String ByRef)
--------------------------------
   at d.(  , System.String, System.IO.Stream)
   at ThirdPartyClass.Save(System.String, System.IO.Stream)
   at FirstPartyClass.CreateImage()
   at FirstPartyClass.Execute()
   at System.Threading.ThreadHelper.ThreadStart_Context(System.Object)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart()

Edit: Adding more information. I did read this similar post: Gracefully handling corrupted state exceptions in .NET Core Which does not bode well for my problem. My question does differ though, because I don't care to catch the exceptions, I'm ok with the application crashing. I just want to ensure we can log this information to our log provider of choice when these errors do occur.

cjablonski76
  • 173
  • 1
  • 13

2 Answers2

0

İf you didn't try, you can use ILogger interface or Serilog package. You can find helper documentation from the below links.

Logging in .NET Core and ASP.NET Core

Serilog

M. Erim Tuzcuoglu
  • 337
  • 1
  • 7
  • Do you happen to know with any certainty whether Serilog will capture these types of exceptions by chance? I will do a POC with Serilog to see for sure, but still curious if you already know the answer before I even put pen to paper :) – cjablonski76 Jul 22 '21 at 20:40
0

To get the unhandled exceptions like this, ensure you are calling UseExceptionHandler

In the below link search for "Catches and logs unhandled exceptions"

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/error-handling?view=aspnetcore-5.0

In the startup class, look for the function

public void Configure

In that function, ensure you called UseExceptionHandler as shown below, as mentioned in the document.

if (env.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}
else
{
    app.UseExceptionHandler("/Error");
    app.UseHsts();
}
Pavan Chandaka
  • 11,671
  • 5
  • 26
  • 34