Integrated: 8343855: HTTP/2 ConnectionWindowUpdateSender may miss some unprocessed DataFrames from closed streams

[Daniel Fuchs]

On Fri, 8 Nov 2024 17:42:22 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

> [JDK-8342075](https://bugs.openjdk.org/browse/JDK-8342075) has introduced more flow controls checks, but also introduced a race condition where DataFrames for closed streams may fail to be discounted from the connection window.
> 
> The consequence is that WINDOW_UPDATE frames for the connection window may not be sent when they should, preventing the server from making progress and stalling the connection.
> 
> This can be shown by modifying the StreamFlowControlTest to send less but bigger frames (e.g. chunks of 1600 bytes instead of chunks of 12 bytes). With such a modification the test can be seen failing intermittently, when sameClient=true.
> 
> The race happens when frames that have been added to Stream::inputQ fail to be drained after the stream is closed (or continue to be added to the inputQ after the stream is closed).
> 
> The fix ensures that Stream::drainInputQueue() is called when the stream is closed, and that no further data farme will be added to the inputQ after the stream is marked closed.
> 
> The modified StreamFlowControlTest could be observed failing relatively frequently on linux-aarch64 without the fix.
> With the fix the test no longer fails.

This pull request has now been integrated.

Changeset: bd6152f5
Author:    Daniel Fuchs <dfuchs at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/bd6152f5967107d7b32db9bcfa224fc07314f098
Stats:     186 lines in 5 files changed: 146 ins; 6 del; 34 mod

8343855: HTTP/2 ConnectionWindowUpdateSender may miss some unprocessed DataFrames from closed streams

Reviewed-by: jpai

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PR: https://git.openjdk.org/jdk/pull/21991