8367721: Test compiler/arguments/TestCompileTaskTimeout.java crashed: SIGSEGV

[mhaessig]

The test TestCompileTaskTimeout.java runs java -Xcomp -XX:CompileTaskTimeout=1 --version to demonstrate that the timeout works. Part of the timeout working involves it printing the method of the compile task. Inspecting the core file of the execution that failed with a SIGSEGV in the compile task timeout signal handler, the backtrace looks as follows:

#n   <called signal handler>
#n+1 CompilerThreadTimeoutLinux::signal_handler()
#n+2 <called signal handler>
#n+3 timer_settime()
#n+4 CompilerThreadTimeoutLinux::disarm()
#n+5 CompileTaskWrapper::~CompileTaskWrapper()

So, the compile task hit the timeout during destruction of the underlying CompileTaskWrapper. Since the timeout was disarmed only after setting the task to null in the destructor, the signal handler segfaulted when trying to access the method of the compile task to print it out. This PR addresses this issue by moving up the disarmament of the timeout to the top of the destructor.

Because this issue can only be triggered with bad --- or good, depending on your view --- luck on timing, I could not devise a regression test. But this is not too big of an issue, since the CI already caught this issue.

Testing:

• Github Actions
• tier1,tier2,tier3 plus stress testing on Oracle supported platforms

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8367721: Test compiler/arguments/TestCompileTaskTimeout.java crashed: SIGSEGV (Bug - P4)

Reviewers

• Marc Chevalier (@marc-chevalier - Committer)
• Christian Hagedorn (@chhagedorn - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27331/head:pull/27331
$ git checkout pull/27331

Update a local copy of the PR:
$ git checkout pull/27331
$ git pull https://git.openjdk.org/jdk.git pull/27331/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27331

View PR using the GUI difftool:
$ git pr show -t 27331

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27331.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back mhaessig! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@mhaessig This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8367721: Test compiler/arguments/TestCompileTaskTimeout.java crashed: SIGSEGV

Reviewed-by: mchevalier, chagedorn

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 36 new commits pushed to the master branch:

• 4c5e901: 8367689: Revert removal of several compilation-related vmStructs fields
• a306f88: 8339791: Refactor MiscUndecorated/ActiveAWTWindowTest.java
• a355edb: 8367278: Test compiler/startup/StartupOutput.java timed out after completion on Windows
• ... and 33 more: https://git.openjdk.org/jdk/compare/c82070e6357a1b49f2887ab22267393ba87d9352...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

@mhaessig The following label will be automatically applied to this pull request:

• hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (c2af5f34)

[marc-chevalier]

That makes a lot of sense to me.

If I understand well, it happens when the compile task is naturally terminating, when compilation is done in pretty much the delay granted by the timeout. It doesn't come from the concurrent handling of the timeout and some other kind of error?

[mhaessig]

Thank you for taking a look, @marc-chevalier.

It doesn't come from the concurrent handling of the timeout and some other kind of error?

There is only one timeout going on for every compile task and thus for every compiler thread and they are delivered directly to the native thread running the compiler thread with the timed out compile task. Since CompileTasks are thread local, this cannot come from concurrent timeouts. I can successfully exclude other kinds of errors, because the timeout signal handler does not have any other ways to segfault other than on accessing the task, because it does not use any of the pointers passed to it.

[chhagedorn]

Looks good to me, too!

[mhaessig]

Thank you for your reviews, @chhagedorn and @marc-chevalier!

/integrate

[openjdk]

Going to push as commit 04dcaa3.
Since your change was applied there have been 36 commits pushed to the master branch:

• 4c5e901: 8367689: Revert removal of several compilation-related vmStructs fields
• a306f88: 8339791: Refactor MiscUndecorated/ActiveAWTWindowTest.java
• a355edb: 8367278: Test compiler/startup/StartupOutput.java timed out after completion on Windows
• ... and 33 more: https://git.openjdk.org/jdk/compare/c82070e6357a1b49f2887ab22267393ba87d9352...master

Your commit was automatically rebased without conflicts.

[openjdk]

@mhaessig Pushed as commit 04dcaa3.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.