Application info:

• TargetFramework: .NET 5
• Project type: Microsoft.NET.Sdk.Worker

For a few days now, my application sometimes hangs (deadlock?) after an await call to FindAsync of an IMongoCollection.

For example:

var testCursor = await testCollection.FindAsync(_ => true);

the same also happens for:

var testCursor = await testCollection.FindAsync(_ => true).ConfigureAwait(false);

Any line after this call is never reached.

The problem might happen because I use the API in a wrong way somewhere, but I wasn't able to recreate a minimal code example to reproduce the issue yet.

However, the deadlock always happens at this line: https://github.com/mongodb/mongo-csharp-driver/blob/51b48437814cd6d1f4882d1ca2387b1539c8f01f/src/MongoDB.Driver.Core/Core/ConnectionPools/ExclusiveConnectionPool.cs#L227

MaintainSizeAsync().ConfigureAwait(false);

I don't know if that line is not using await on purpose, but I figured it might be an oversight and I post what I found anyway to make sure it is at least checked by a developer who knows more about the code.

If I manage to create a minimal reproducible example, I will let you know.