RFR: 8287233: Crash in Continuation.enterSpecial: stop: tried to execute native method as non-native

[David Holmes]

On Fri, 27 May 2022 15:53:25 GMT, Ron Pressler <rpressler at openjdk.org> wrote:

> Please review this fix to a continuation-related crash that happens due to a race between the linking and generation of Continuation.enterSpecial.
> 
> Passes Loom tiers 1-5.

I have one suggested change below, but in general enforcing strict storestore ordering seems to address the issue observed.

Thanks.

src/hotspot/share/oops/method.cpp line 1335:

> 1333:     // This must come last, as it is what's tested in LinkResolver::resolve_static_call
> 1334:     mh->_from_interpreted_entry = mh->get_i2c_entry();
> 1335:     OrderAccess::storestore();

Technically this needs a release-store to pair with the load-acquire.

But what subsequent store is this final store being ordered with? If there is none then it would suffice for this sequence to be just:

    mh->_i2i_entry = mh->get_i2c_entry();
    // This must come last, as it is what's tested in LinkResolver::resolve_static_call
    Atomic::release_store(&mh->_from_interpreted_entry , mh->get_i2c_entry());

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Changes requested by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/8926