RFR: 8360201: JFR: Initialize JfrThreadLocal::_sampling_critical_section [v2]

[Aleksey Shipilev]

On Tue, 24 Jun 2025 07:28:20 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> Restarted ubsan-ized builds with your patch included + tests afterwards did not show the issue on Linux aarch64 where it showed up previously.

Thanks for testing!

> Do we maybe have the chance to set (on some compiler toolchains) warning flags to see such uninitialized fields issues without more 'heavyweight' tools like ubsan ? Or do we want to keep sometimes some fields uninitialized in the constructors so those warning flags would not work for us ?

Maybe, but I see that e.g. `maybe-uninitialized` is globally disabled. It would probably require massaging quite a bit of code to avoid the warning, assuming the compiler analysis is even 100% correct. I would think @kimbarrett knows much more context here.

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PR Comment: https://git.openjdk.org/jdk/pull/25938#issuecomment-3000367199