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avoid NRE in MsQuicConnection ConnectAsync #56283

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Merged
merged 7 commits into from
Jul 29, 2021
Merged

avoid NRE in MsQuicConnection ConnectAsync #56283

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f9e3284
avoid NRE in MsQuicConnection ConnectAsync
wfurt Jul 26, 2021
dbc0830
Merge branch 'main' of https://github.com/dotnet/runtime into nre_56263
wfurt Jul 27, 2021
6f3901f
enable disabled test
wfurt Jul 27, 2021
dccf730
one more place where we set ConnectTcs to null
wfurt Jul 27, 2021
4c5e6de
use local variable
wfurt Jul 27, 2021
1d906fb
Merge branch 'main' of https://github.com/dotnet/runtime into nre_56263
wfurt Jul 29, 2021
9426974
feedback from review
wfurt Jul 29, 2021
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11 changes: 7 additions & 4 deletions src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/MsQuicConnection.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -227,6 +227,7 @@ private static uint HandleEventConnected(State state, ref ConnectionEvent connec

state.Connected = true;
state.ConnectTcs!.SetResult(MsQuicStatusCodes.Success);
state.ConnectTcs = null;
}

return MsQuicStatusCodes.Success;
Expand Down Expand Up @@ -576,7 +577,8 @@ internal override ValueTask ConnectAsync(CancellationToken cancellationToken = d
throw new Exception($"Unsupported remote endpoint type '{_remoteEndPoint.GetType()}'.");
}

_state.ConnectTcs = new TaskCompletionSource<uint>(TaskCreationOptions.RunContinuationsAsynchronously);
// We store TCS to local variable to avoid NRE if callbacks finish fast and set _state.ConnectTcs to null.
var tcs = _state.ConnectTcs = new TaskCompletionSource<uint>(TaskCreationOptions.RunContinuationsAsynchronously);

try
{
Expand All @@ -600,7 +602,7 @@ internal override ValueTask ConnectAsync(CancellationToken cancellationToken = d
throw;
}

return new ValueTask(_state.ConnectTcs.Task);
return new ValueTask(tcs.Task);
}

private ValueTask ShutdownAsync(
Expand Down Expand Up @@ -683,9 +685,10 @@ private static uint NativeCallbackHandler(

if (state.ConnectTcs != null)
{
state.ConnectTcs.SetException(ex);
state.ConnectTcs = null;
// This is opportunistic if we get exception and have ability to propagate it to caller.
state.ConnectTcs.TrySetException(ex);
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@stephentoub stephentoub Jul 27, 2021

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This is the change I was hinting at when asking about the race condition.

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@wfurt wfurt Jul 27, 2021

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I think I can do better fix. Instead of checking state of the task I can simply store TaskCompletionSource in ConnectAsync to local variable and return that. There is really no reason to drag it past Connect event.

state.Connection = null;
state.ConnectTcs = null;
}
else
{
Expand Down
2 changes: 0 additions & 2 deletions src/libraries/System.Net.Quic/tests/FunctionalTests/MsQuicTests.cs
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Expand Up @@ -152,7 +152,6 @@ public async Task CertificateCallbackThrowPropagates()
}

[Fact]
[ActiveIssue("https://github.com/dotnet/runtime/issues/56263")]
public async Task ConnectWithCertificateCallback()
{
X509Certificate2 c1 = System.Net.Test.Common.Configuration.Certificates.GetServerCertificate();
Expand Down Expand Up @@ -235,7 +234,6 @@ public async Task ConnectWithCertificateCallback()
}

[Fact]
[ActiveIssue("https://github.com/dotnet/runtime/issues/56454")]
public async Task ConnectWithCertificateForDifferentName_Throws()
{
(X509Certificate2 certificate, _) = System.Net.Security.Tests.TestHelper.GenerateCertificates("localhost");
Expand Down