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  1. C# Driver
  2. CSHARP-3477

Potential deadlock in ExclusiveConnectionPool (MaintainSizeAsync)

    • Type: Icon: Bug Bug
    • Resolution: Gone away
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 2.12.0
    • Component/s: API
    • None
    • Environment:
      TargetFramework: .NET 5
      Project type: Microsoft.NET.Sdk.Worker
      OS: Windows 10
      MongoDB: Community Edition 4.4.3 2008R2Plus SLL (64 bit) - installed as Windows Service

      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.

            Assignee:
            james.kovacs@mongodb.com James Kovacs
            Reporter:
            inuriasx@gmail.com Raphael Rabl
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              Created:
              Updated:
              Resolved: