On Thu, 16 Feb 2023 09:51:27 GMT, Daniel Fuchs <[email protected]> wrote:
> The HttpBodySubscriberWrapper is a class that ensures that a subscriber will
> be subscribed to before it is completed. It also provides hooks to its two
> subclasses (one for HTTP/1, one for HTTP/2) that allows subclasses to
> register the susbscriber with the HttpClient at subscription time, and to
> unregister it when it is eventualy completed, or when the subscription is
> cancelled.
>
> There is however a race condition that can happen when a subscription is
> cancelled: it can happen that unregister is called before register. The
> CancelRequestTest has been observed failing once or twice on personal jobs.
> Though the particular mechanics of this race is hard to understand, the logs
> of the tests have brought sufficient evidence that this is what was
> happening.
>
> The symptom is finding one subscriber still registered after completion of
> the exchange:
>
> test
> CancelRequestTest.testGetSendAsync("https://localhost:42711/https1/x/same/interrupt";,
> true, true): failure
> java.lang.AssertionError: WARNING: tracker for HttpClientImpl(13) has
> outstanding operations:
> Pending HTTP Requests: 0
> Pending HTTP/1.1 operations: 0
> Pending HTTP/2 streams: 0
> Pending WebSocket operations: 0
> Pending TCP connections: 0
> Pending Subscribers: 1
> Total pending operations: 0
> Facade referenced: true
> Selector alive: true
>
> The proposed fix hoist special hooks for register/unregister in the
> superclass, merges all various volatile boolean states into a single int
> state, and protect the state changes to subscribed/register/unregister by
> the same subscription lock.
> If cancelling the subscription happens at around the same time that the
> subscriber is subscribed this ensures that the subscriber won't be removed
> from the map before it is added.
This pull request has now been integrated.
Changeset: edf238b6
Author: Daniel Fuchs <[email protected]>
URL:
https://git.openjdk.org/jdk/commit/edf238b65e441a1d626f3a4ba06170badd05ca7c
Stats: 235 lines in 4 files changed: 190 ins; 22 del; 23 mod
8302635: Race condition in HttpBodySubscriberWrapper when cancelling request
Reviewed-by: jpai
-------------
PR: https://git.openjdk.org/jdk/pull/12587
