On Wed, 20 Aug 2025 15:43:03 GMT, Evgeny Astigeevich <[email protected]> wrote:
>> There is a race between `JvmtiClassFileReconstituter::copy_bytecodes` and >> `InstanceKlass::link_class_impl`. `InstanceKlass::link_class_impl` can be >> rewriting bytecodes. `JvmtiClassFileReconstituter::copy_bytecodes` will not >> restore them to the original ones because the flag `rewritten` is `false`. >> This will result in invalid bytecode. >> >> This PR adds a lock (`init_lock`) to the `copy_bytecodes` method to prevent >> reading bytecodes while they are being rewritten during class linking. >> >> Tested fastdebug and release builds: Linux x86_64 and arm64 >> - The reproducer from JDK-8277444 passed. >> - Tier1 - tier3 passed. > > Hi @coleenp, > Could you please take a look? @eastig I am not sure about this one. Can you clarify please how you can be transforming a class that has not yet been linked? If this is possible then it seems to me we are missing a call to ensure linkage. ------------- PR Comment: https://git.openjdk.org/jdk/pull/26863#issuecomment-3208497225
