8253435: Cgroup: 'stomping of _mount_path' crash if manually mounted cpusets exist

[jmtd]

This is a backport of JDK-8253435 (Cgroup: 'stomping of mount path' crash if
manually mounted cpusets exist) as part of an effort to backport cgroups v2
support for JDK 11.

It applies clean after the dependent pr/986 (8252359: HotSpot Not Identifying
it is Running in a Container) and the included test passes for me on a pure
cgroups v2 system.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8253435: Cgroup: 'stomping of _mount_path' crash if manually mounted cpusets exist

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk11u-dev pull/992/head:pull/992
$ git checkout pull/992

Update a local copy of the PR:
$ git checkout pull/992
$ git pull https://git.openjdk.java.net/jdk11u-dev pull/992/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 992

View PR using the GUI difftool:
$ git pr show -t 992

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk11u-dev/pull/992.diff

[bridgekeeper]

👋 Welcome back jdowland! A progress list of the required criteria for merging this PR into pr/986 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 02: Full (4d362ad8)
• 01: Full - Incremental (a880241a)
• 00: Full (a880241a)

[openjdk-notifier]

The dependent pull request has now been integrated, and the target branch of this pull request has been updated. This means that changes from the dependent pull request can start to show up as belonging to this pull request, which may be confusing for reviewers. To remedy this situation, simply merge the latest changes from the new target branch into this pull request by running commands similar to these in the local repository for your personal fork:

git checkout jmtd-backport-76f0588a
git fetch https://git.openjdk.java.net/jdk11u-dev master
git merge FETCH_HEAD
# if there are conflicts, follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk]

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

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

8253435: Cgroup: 'stomping of _mount_path' crash if manually mounted cpusets exist

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[jmtd]

/integrate

[openjdk]

@jmtd
Your change (at version 4d362ad) is now ready to be sponsored by a Committer.

[jerboaa]

/sponsor

[openjdk]

Going to push as commit 19ccccc.

[openjdk]

@jerboaa @jmtd Pushed as commit 19ccccc.

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