RFR: 8377512: AOT cache creation fails with invalid native pointer
Ioi Lam
iklam at openjdk.org
Mon Feb 23 01:00:38 UTC 2026
Since JDK 25, we have two bugs that cause a pointer to an excluded class to be referenced by a cached heap object.
[1] Method references to excluded classes:
interface A {
Object get();
}
...
A a = ShouldBeExcluded::new; // line 1
[2] Invocation of a `MethodHandle` whose `MethodType` includes an excluded class:
MethodHandle constructorHandle =
MethodHandles.lookup().unreflectConstructor(ShouldBeExcluded.class.getConstructor());
// The JVM rewrites the following invoke() from
// invokevirtual <java/lang/invoke/MethodHandle.invoke()LShouldBeExcluded;>
// to
// invokehandle <java/lang/invoke/MethodHandle.invoke()LShouldBeExcluded;>
ShouldBeExcluded o = (ShouldBeExcluded)constructorHandle.invoke(); // line 2
In the above examples, during the training run, the AOT configuration file records the fact that the constant pool entries used by line 1 and line 2 have been resolved. Normally, these references are resolved by AOTConstantPoolResolver during the assembly phase (to improve start-up time).
However, resolving these 2 entries would cause an invalid `MethodType` that references the `ShouldBeExcluded` class to be add into `MethodType::internTable`. Once this happens, it's very difficult for to recover from.
Therefore, this PR tries to avoid adding such invalid `MethodType` by avoiding the resolution of such constant pool entries.
Thanks to folks at Azul from coming up with the reproducer.
-------------
Commit messages:
- dummy commit
- Added test case from Anton Kozlov
- Handle SignedJarExclusionReproducer.zip test case by Anton Kozlov
- tmp
Changes: https://git.openjdk.org/jdk/pull/29825/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29825&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8377512
Stats: 123 lines in 5 files changed: 110 ins; 2 del; 11 mod
Patch: https://git.openjdk.org/jdk/pull/29825.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/29825/head:pull/29825
PR: https://git.openjdk.org/jdk/pull/29825
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