On Sun, 19 Dec 2021 03:21:55 GMT, liach <d...@openjdk.java.net> wrote:
> Upon review of [8261407](https://bugs.openjdk.java.net/browse/JDK-8261407), > by design, duplicate initialization of ReflectionFactory should be safe as it > performs side-effect-free property read actions, and the suggesting of making > the `initted` field volatile cannot prevent concurrent initialization either; > however, having `initted == true` published without the other fields' values > is a possibility, which this patch addresses. > > This simulates what's done in `CallSite`'s constructor for > `ConstantCallSite`. Please feel free to point out the problems with this > patch, as I am relatively inexperienced in this field of fences and there are > relatively less available documents. (Thanks to > https://shipilev.net/blog/2014/on-the-fence-with-dependencies/) Changes requested by dholmes (Reviewer). src/java.base/share/classes/jdk/internal/reflect/ReflectionFactory.java line 695: > 693: > 694: // ensure previous fields are visible before initted is > 695: Unsafe.getUnsafe().storeStoreFence(); Ensuring ordering on the writer side, without also ensuring ordering on the reader side, doesn't solve an ordering problem. Just make `initted` volatile and this should be safe from a Java Memory Model perspective. ------------- PR: https://git.openjdk.java.net/jdk/pull/6889
