RFR: 8313796: AsyncGetCallTrace crash on unreadable interpreter method pointer [v4]

[Erik Österlund]

On Mon, 7 Aug 2023 21:26:00 GMT, Richard Startin <duke at openjdk.org> wrote:

>> @tstuefe implemented explicitly for being signal safe.
>
> OK let's go with your suggestion, thanks for explaining. I'm actually skeptical this can actually be a non-null bad pointer, as we've only seen this crash happen once, and the pointer was null in that instance. But this solution looks robust, so thanks for suggesting it.

So you can safely fetch something that might be a method, and even if it really is a method and that can be verified, it might be a concurrently unloading method that is about to get clobbered or uncommiyted. Dereferencing and using such a Method is also subject to occasional crashing. Might be a problem for another day though.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15178#discussion_r1286573306