8345374: Ubsan: runtime error: division by zero

[kimbarrett]

Please review this change to G1HeapSizingPolicy to avoid a float division by
zero when calculating the maximum desired capacity with a MaxHeapFreeRatio
value of 100%.

Testing: mach5 tier1 with G1 and MaxHeapFreeRatio=100.

---

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-8345374: Ubsan: runtime error: division by zero (Bug - P4)

Reviewers

• Julian Waters (@TheShermanTanker - Committer)
• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Amit Kumar (@offamitkumar - Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/22893/head:pull/22893
$ git checkout pull/22893

Update a local copy of the PR:
$ git checkout pull/22893
$ git pull https://git.openjdk.org/jdk.git pull/22893/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 22893

View PR using the GUI difftool:
$ git pr show -t 22893

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/22893.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back kbarrett! 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]

@kimbarrett 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:

8345374: Ubsan: runtime error: division by zero

Reviewed-by: jwaters, ayang, amitkumar

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 4 new commits pushed to the master branch:

• d3abf01: 8346101: [JVMCI] Export jdk.internal.misc to jdk.graal.compiler
• 24c5ff7: 8346871: Improve robustness of java/util/zip/EntryCount64k.java test
• bd0fde7: 8302293: jar --create fails with IllegalArgumentException if archive name is shorter than 3 characters
• 7995847: 8346831: Remove the extra closing parenthesis in CTW Makefile

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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]

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

• hotspot-gc

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 (a0480e0f)

[TheShermanTanker]

Doesn't debug.hpp have precond for this?

[kimbarrett]

It does, and hardly anyone uses it.

[TheShermanTanker]

Looks alright, but I think the title needs to be changed to match the one on the tracker

[kimbarrett]

Thanks for reviews @TheShermanTanker , @albertnetymk , and @offamitkumar

[kimbarrett]

/integrate

[openjdk]

Going to push as commit a87bc7e.
Since your change was applied there have been 4 commits pushed to the master branch:

• d3abf01: 8346101: [JVMCI] Export jdk.internal.misc to jdk.graal.compiler
• 24c5ff7: 8346871: Improve robustness of java/util/zip/EntryCount64k.java test
• bd0fde7: 8302293: jar --create fails with IllegalArgumentException if archive name is shorter than 3 characters
• 7995847: 8346831: Remove the extra closing parenthesis in CTW Makefile

Your commit was automatically rebased without conflicts.

[openjdk]

@kimbarrett Pushed as commit a87bc7e.

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