On Thu, 19 Jun 2025 00:45:30 GMT, David Holmes <dhol...@openjdk.org> wrote:
> This still seems racy though. What if the lookup succeeds but at the same
> time the class is to be unloaded?
Yes, It won't be at the same time, since lookup and remove_jmethod_ids hold the
JmethodIdCreation_lock. But this is a good question. It could be still a race:
Method* Method::checked_resolve_jmethod_id(jmethodID mid) {
if (mid == nullptr) return nullptr;
Method* o = resolve_jmethod_id(mid);
if (o == nullptr) {
return nullptr;
}
// Method should otherwise be valid. Assert for testing.
assert(is_valid_method(o), "should be valid jmethodid");
// If the method's class holder object is unreferenced, but not yet marked as
// unloaded, we need to return null here too because after a safepoint, its
memory
// will be reclaimed.
return o->method_holder()->is_loader_alive() ? o : nullptr;
}
I think this should prevent this race but I'd have to think about it some more.
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PR Comment: https://git.openjdk.org/jdk/pull/25267#issuecomment-2992814813
