RFR: 8276205: Shenandoah: CodeCache_lock should always be held for initializing code cache iteration

[Zhengyu Gu]

On Mon, 1 Nov 2021 16:49:46 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> > > ShenandoahConcurrentRootScanner
> > 
> > 
> > Does it matter?
> 
> You tell me, I think it would be full of dangling references after we are done with scanner? The similar reason why we do `_table = NULL` in a similar method in another iterator. You don't have to change it here, but maybe a simple cleanup for later.

Yea, there is inconsistent among these iterators. The code is in destructors, I don't see it matters, cause accessing dangling references in a deallocated object is a fatal bug.

-------------

PR: https://git.openjdk.java.net/jdk/pull/6192