On Thu, 20 Mar 2025 08:37:45 GMT, Volkan Yazici <vyaz...@openjdk.org> wrote:
> Guards against multi-deletes in `UnixSocketChannelReadWrite`. > > The fix can be verified as follows: > > > make build-microbenchmark > build/linux-x64/jdk/bin/java \ > -jar build/linux-x64/images/test/micro/benchmarks.jar \ > -f 1 -wi 1 -i 1 -t 2 UnixSocketChannelReadWrite > > > Note that `-t 2` denotes the number of worker threads, i.e., parallelism. > > > Seems like the only explanation for why that is happening is someone > > > cleaning out /tmp while the test is running > > > > > > @Michael-Mc-Mahon No, the reason for the failure is multiple threads > > creating a Unix socket in the very same `tempDir`, and then trying to > > delete the `tempDir`. See the following execution flow involving multiple > > threads: > > ``` > > 1. `tempDir` is statically assigned during class initialization (say > > `/tmp/readWriteTest2414375588689416060`) > > > > 2. `Thread1` runs `beforeRun()`, which creates the Unix socket > > `/tmp/readWriteTest2414375588689416060/1` > > > > 3. `Thread2` runs `beforeRun()`, which creates the Unix socket > > `/tmp/readWriteTest2414375588689416060/2` > > > > 4. Both `Thread1` and `Thread2` runs `afterRun()` in parallel > > > > 5. `Thread1` runs `Files.delete(/tmp/readWriteTest2414375588689416060/1)` > > and succeeds > > > > 6. `Thread2` runs `Files.delete(/tmp/readWriteTest2414375588689416060/2)` > > and succeeds > > > > 7. `Thread1` runs `Files.delete(/tmp/readWriteTest2414375588689416060)` and > > succeeds (since both `/1` and `/2` socket files are removed above, and, > > hence, the directory is empty) > > > > 8. `Thread2` runs `Files.delete(/tmp/readWriteTest2414375588689416060)` and > > fails, since the directory has already been deleted above > > ``` > > > > > > > > > > > > > > > > > > > > > > > > Ideally, `tempDir` deletion should be performed by a single thread. But > > replacing `Files::delete` with `Files::deleteIfExists` also does the job, > > at a lower cost. > > What would happen then if thread1 completes before thread2 starts? Maybe, we > _should_ delete the directory in a separate block, executed in a single > thread at the every end. Is there a variant of the @teardown() annotation > which executes at the end of the test? maybe the directory could be created and deleted in separate @teardown(Level.Trial) invocations ? ------------- PR Comment: https://git.openjdk.org/jdk/pull/24126#issuecomment-2747920277
