8299790: os::print_hex_dump is racy

[tstuefe]

Hi all,

This pull request contains a backport of commit 8f28809a from the openjdk/jdk repository.

The commit being backported was authored by Thomas Stuefe on 10 Aug 2023 and was reviewed by Aleksey Shipilev and David Holmes.

Thanks!

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8299790 needs maintainer approval

Issue

• JDK-8299790: os::print_hex_dump is racy (Bug - P4 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/824/head:pull/824
$ git checkout pull/824

Update a local copy of the PR:
$ git checkout pull/824
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/824/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 824

View PR using the GUI difftool:
$ git pr show -t 824

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/824.diff

Webrev

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[bridgekeeper]

👋 Welcome back stuefe! 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]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

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

[openjdk]

⚠️ @tstuefe This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (30f483f8)

[tstuefe]

/approval request I would like to downport this fix since this is a bug (admittedly, with limited consequences: printing potentially unreadable sections should only done during hs-err printing, so all it would do is mess up hs-err files). But it is also a prerequisite for downporting JDK-8334738, which would be very useful to have, e.g. in the context of dealing with reproducible builds and CDS dumps.

The fix itself is low risk, but it introduced a test error for big-endian platforms, which was fixed subsequently with https://bugs.openjdk.org/browse/JDK-8314163. I will backport that one without delay once this patch is pushed.

[openjdk]

@tstuefe
8299790: The approval request has been created successfully.