RFR: 8361873: [GCC static analyzer] exec_md.c forkedChildProcess potential double 'close' of file descriptor '3'

[Jaikiran Pai]

On Fri, 25 Jul 2025 23:09:48 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

> Fix gcc warning about double close. forkedChildProcess() calls closeDescriptors(), which always closes STDERR_FILENO + 1 and STDERR_FILENO + 2. However, if it fails at some point after that, then forkedChildProcess() will attempt to close these same two files again. Fixed by making forkedChildProcess() no longer attempt to close these two files.
> 
> I first verified the warning by configuring with --with-extra-cflags=-fanalyzer, and then verified the fix by doing the same.
> 
> Tested by running jdi nsk test. I'll add some more CI testing.

This looks reasonable to me. I just have trivial comment about the code comment introduced in this change, which I've added inline.

src/jdk.jdwp.agent/unix/native/libjdwp/exec_md.c line 82:

> 80:      * descriptors afresh.
> 81:      *
> 82:      * WARNING: We are not allowed to fail until after these two closes are

Hello Chris, would it be better to word this as "We are not allowed to return from this function until after ...."?

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Marked as reviewed by jpai (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26487#pullrequestreview-3059210605
PR Review Comment: https://git.openjdk.org/jdk/pull/26487#discussion_r2233741615