RFR: 8261354: SIGSEGV at MethodIteratorHost

[Markus Grönlund]

On Fri, 21 May 2021 09:56:40 GMT, Jaroslav Bachorik <jbachorik at openjdk.org> wrote:

> The `MethodIteratorHost` will iterate over previous versions of redefined classes but the number of methods in that class is retrieved only for the current version. 
> Since the previous versions may theoretically, and before JDK 15 also practically, contain fewer methods than the current version (hotspot did support adding `private static` methods during retransformation) this can lead to SIGSEGV when the iterator tries accessing out-of-range method element.
> 
> Although for after JDK 15 it is not possible to have differing number of methods between multiple versions of a retransformed class it feels right not to rely on the implementation detail and re-retrieve the number of methods per each class version.
> 
> All jdk_jfr tests are passing on Linux x64 and MacOS x64

Hi again,

I noticed the Filter stuff after I clicked Approve, and it was an attempt to roll back my approve state - I don't know if it is possible to even do that. So consider it approved, but we need to think about how to handle the Filter thing. Because now it will no longer work as intended, so maybe consider removing it.

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PR: https://git.openjdk.java.net/jdk/pull/4143