[jdk11u-dev] RFR: 8272124: Cgroup v1 initialization causes NullPointerException when cgroup path contains colon

[Severin Gehwolf]

On Tue, 24 Aug 2021 17:34:28 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

> Please review this defensive backport of JDK-8272124. OpenJDK 11u is affected too, but it manifests in a different way. Basically Java metrics report wrong results on affected system where the cgroup path contains a colon. The JDK 18 patch doesn't apply cleanly since JDK-8230305 (cgroups v2 support) isn't in 11u. Test support in 11 isn't as good as well (files don't exist), thus dropped the test changes.
> 
> Also, I've kept the token number filter to keep using `>=  3` since that's the more defensive approach. It's not clear if systems with `/proc/self/cgroup` files exist in the wild with less than 3 tokens.
> 
> Testing: Manual reproduce before/after patch. See explicit backport bug for details.
> 
> Thoughts?

Thanks for the review!

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/292