On Wed, 5 Aug 2026 11:30:03 GMT, Jaikiran Pai <[email protected]> wrote:

>> Can I please get a review of this test-only fix to the 
>> `test/jdk/java/net/Socket/SocketReadInterruptTest.java` test that fails 
>> intermittently? This addresses https://bugs.openjdk.org/browse/JDK-8383768.
>> 
>> The test was introduced back in JDK 16 when addressing 
>> https://bugs.openjdk.org/browse/JDK-8237858. The (old) `PlainSocketImpl` 
>> based `java.net.Socket` implementation at that time had a bug where if 
>> "ServerSocket.accept()" was blocked waiting for a connection and if the 
>> native `accept()` call returned `EINTR` due to that system call being 
>> terminated by a signal, then the Java application would end up incorrectly 
>> receiving a `java.net.SocketTimeoutException: Accept timed out` exception. 
>> That issued was fixed in JDK 16 and a couple of new jtreg tests were 
>> introduced to verify the fix. This `SocketReadInterruptTest` was one of 
>> those. Details of that fix and the test introduction are available in the 
>> RFR email at that time:
>> 
>> https://mail.openjdk.org/pipermail/net-dev/2020-March/013637.html
>> and
>> https://mail.openjdk.org/pipermail/net-dev/2020-March/013646.html
>> 
>> The old `PlainSocketImpl` implementation of `java.net.Socket` is no longer 
>> present in the JDK mainline. However, I think the idea is still a valid one 
>> to verify that the Java application doesn't receive an unexpected exception 
>> when it is blocked on `ServerSocket.accept()` or `Socket.read()` and the 
>> `accept()` or `read()` system calls returned with `EINTR`. So the 
>> `SocketReadInterruptTest` (and the `SocketAcceptInterruptTest`), I think are 
>> still good to have in the JDK mainline.
>> 
>> The `SocketReadInterruptTest` has been failing intermittently. What the test 
>> does is, it creates a `ServerSocket`, then `accept()`s the connection from 
>> the test's `Socket`. The test then initiates a `Socket.read()` with a socket 
>> read timeout of 3 seconds. On the server side, the `ServerSocket` after 
>> accepting the connection will wait for 2 seconds before writing out a 
>> response on the accepted socket's outputstream.
>> 
>> When the client side is waiting in `Socket.read()` (for a duration of 3 
>> seconds), the test sends out a signal to the native thread which is blocked 
>> on the `read()` system call. This it does so that the `read()` system call 
>> returns with a `EINTR`. The test then expects that no exception propagates 
>> to the `Socket.read()` call and instead the `Socket.read()` completes 
>> normally. This works fine in most cases.
>> 
>> However, on certain occasions, if the server thread which is responsible for 
>> writing...
>
> Jaikiran Pai has updated the pull request with a new target base due to a 
> merge or a rebase. The incremental webrev excludes the unrelated changes 
> brought in by the merge/rebase. The pull request contains six additional 
> commits since the last revision:
> 
>  - Add a comment to clarify a test class method
>  - merge latest from master branch
>  - Daniel's suggestion - use CompletableFuture instead of CountDownLatch
>  - add newline add end of file
>  - merge latest from master branch
>  - 8383768: java/net/Socket/SocketReadInterruptTest.java failed with 
> SocketTimeoutException: Read timed out

Thank you Daniel for the review.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/32051#issuecomment-5242382838

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