8283469: Don't use memset to initialize members in FileMapInfo and fix memory leak

[zhengyu123]

I would like to backport this patch to 17u, to fix a memory leak, also eliminates dangerous memset call, could potentially result in fatal crash.

The original patch does not apply cleanly, due to JDK-8261455, where it changed FileMapInfo's constructor signature to pass in full_path as a parameter. The conflict is resolved manually by initializing _full_path to nullptr.

I also bought down following code from JDK-8261455, given it is a P4 enhancement, I don't see it is a candidate for backport itself. But following code obviously fixes a bug that leaves file open after use.

  if (_file_open) {
    os::close(_fd);
  }

Test:

• hotspot_cds on Linux x86_64
• GHA

---

Progress

• Change must not contain extraneous whitespace
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• Change must be properly reviewed (1 review required, with at least 1 reviewer)

Issue

• JDK-8283469: Don't use memset to initialize members in FileMapInfo and fix memory leak

Reviewers

• Martin Doerr (@TheRealMDoerr - Reviewer) ⚠️ Review applies to 63f416a5

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk17u-dev pull/397/head:pull/397
$ git checkout pull/397

Update a local copy of the PR:
$ git checkout pull/397
$ git pull https://git.openjdk.java.net/jdk17u-dev pull/397/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 397

View PR using the GUI difftool:
$ git pr show -t 397

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk17u-dev/pull/397.diff

[bridgekeeper]

👋 Welcome back zgu! 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 backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 01: Full - Incremental (d102de92)
• 00: Full (63f416a5)

[TheRealMDoerr]

Backport lgtm. Please add empty line before integrating.

[TheRealMDoerr]

Original change adds an empty line here. Please insert.

[zhengyu123]

Fixed. Thanks for the review, @TheRealMDoerr

[openjdk]

@zhengyu123 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:

8283469: Don't use memset to initialize members in FileMapInfo and fix memory leak

Reviewed-by: mdoerr

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:

• 2680e83: 8285728: Alpine Linux build fails with busybox tar
• cc91c6e: 8284758: [linux] improve print_container_info
• 7c87493: 8284754: print more interesting env variables in hs_err and VM.info
• 5c1835d: 8283323: libharfbuzz optimization level results in extreme build times

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.

[zhengyu123]

/integrate

[openjdk]

Going to push as commit 0355888.
Since your change was applied there have been 7 commits pushed to the master branch:

• ab81cd0: 8286293: Tests ShortResponseBody and ShortResponseBodyWithRetry should use less resources
• 676b097: 8236136: tests which use CompilationMode shouldn't be run w/ TieredStopAtLevel
• fc81c86: 8285686: Update FreeType to 2.12.0
• 2680e83: 8285728: Alpine Linux build fails with busybox tar
• cc91c6e: 8284758: [linux] improve print_container_info
• 7c87493: 8284754: print more interesting env variables in hs_err and VM.info
• 5c1835d: 8283323: libharfbuzz optimization level results in extreme build times

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit 0355888.

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