8277100: Dynamic dump can inadvertently overwrite default CDS archive

[calvinccheung]

Please review this small fix for preventing the default CDS archive from being overwritten via the
-XX:ArchiveClassesAtExit VM option.

If the user sets the -XX:ArchiveClassesAtExit option pointing to the default CDS archive, VM will
exit with the following message:

Cannot specify the default CDS archive for -XX:ArchiveClassesAtExit: <path to classes.jsa>

Passed CI tiers 1 and 2 tests.

---

Progress

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

Issue

• JDK-8277100: Dynamic dump can inadvertently overwrite default CDS archive

Reviewers

• Ioi Lam (@iklam - Reviewer)
• Yumin Qi (@yminqi - Reviewer)
• David Holmes (@dholmes-ora - Reviewer)

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/6896/head:pull/6896
$ git checkout pull/6896

Update a local copy of the PR:
$ git checkout pull/6896
$ git pull https://git.openjdk.java.net/jdk pull/6896/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 6896

View PR using the GUI difftool:
$ git pr show -t 6896

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/6896.diff

[calvinccheung]

/label add hotspot-runtime

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[openjdk]

@calvinccheung
The hotspot-runtime label was successfully added.

[mlbridge]

Webrevs

• 00: Full (c84ee718)

[iklam]

LGTM

[yminqi]

LGTM.

[openjdk]

@calvinccheung 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:

8277100: Dynamic dump can inadvertently overwrite default CDS archive

Reviewed-by: iklam, minqi, dholmes

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 3 new commits pushed to the master branch:

• 4c78c9a: 8270929: Obsolete the FilterSpuriousWakeups flag in JDK 19
• 06206c7: 8278949: Cleanups for 8277850
• 31fbb87: 6462028: MaskFormatter API documentation refers to getDisplayValue

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.

[dholmes-ora]

Hi Calvin,

Fix is good, but I have to query whether this is just a P4? I suppose anyone who can overwrite the default archive this way can also restore it with -Xdump, but still this seems a bit of a usability issue worthy of a P3 and fixing in 18.

Thanks,
David

[calvinccheung]

Hi Calvin,

Fix is good, but I have to query whether this is just a P4? I suppose anyone who can overwrite the default archive this way can also restore it with -Xdump, but still this seems a bit of a usability issue worthy of a P3 and fixing in 18.

Thanks, David

Hi David,

I've added a comment to the bug report justifying why this is a P4.
I can backport the fix to 18.

Thanks,
Calvin

[calvinccheung]

@iklam, @yminqi, @dholmes-ora Thanks for the review.
/integrate

[openjdk]

Going to push as commit 8549d8b.
Since your change was applied there have been 3 commits pushed to the master branch:

• 4c78c9a: 8270929: Obsolete the FilterSpuriousWakeups flag in JDK 19
• 06206c7: 8278949: Cleanups for 8277850
• 31fbb87: 6462028: MaskFormatter API documentation refers to getDisplayValue

Your commit was automatically rebased without conflicts.

[openjdk]

@calvinccheung Pushed as commit 8549d8b.

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