RFR: 8309305: sun/security/ssl/SSLSocketImpl/BlockedAsyncClose.java fails with jtreg test timeout [v2]

[Daniel Jeliński]

On Tue, 13 Jun 2023 14:24:20 GMT, Matthew Donovan <mdonovan at openjdk.org> wrote:

>> This PR improves the reliability of the BlockedAsyncClose test by addressing an edge case/race condition between the two test threads. The purpose of the test is to verify that an SSLSocket can be closed if a thread is blocked in a write operation. 
>> 
>> The test starts a "write" thread that writes data to a socket until the output buffer was filled, causing the write operation to block. The main thread then calls `SSLSocket.close()`. The original code used `Thread.sleep(1000)` to wait for the write-thread to block. However, 1 second isn't always long enough and if the write-thread isn't blocked and the output buffer is full (or almost full), the `socket.close()` call may block when it tries to send the close_notify alert. This is the condition that caused this bug.
>> 
>> My change uses a Lock to determine if the write thread is blocked. In the write thread, the lock creates a critical section around the `write()` call. The main thread uses `tryLock()` with a timeout to determine that the write() call is taking too long and thus likely blocked. 
>> 
>> While there, I also updated the test to use the SSLContextTemplate class.
>
> Matthew Donovan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed whitespace.
>   
>   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>

LGTM.
Some OSes spontaneously increase the buffer size after a few seconds, unblocking blocked write operations. We also use 10 seconds limit in networking tests, seems to work pretty well. See https://github.com/openjdk/jdk/blob/9e4fc568a6f1a93c84a84d6cc5220c6eb4e546a5/test/jdk/java/net/httpclient/websocket/PendingOperations.java#L43-L47

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Marked as reviewed by djelinski (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14378#pullrequestreview-1541088196