On Thu, 24 Jul 2025 17:35:23 GMT, Serguei Spitsyn <sspit...@openjdk.org> wrote:

>> Thanks, David. The potential issue I'm still concerned about is that a 
>> subsequent handshaking can also observe the JavaThread (and virtual thread 
>> as well) in a VTMS transition when there is no protection with a 
>> `VTMSTransitionDisabler`.
>
>> Note that java_thread may already be null so we don't get to execute line 
>> 836.
> 
> Right. I guess, this answers my comment about the line 839.

Once in the handshake the carrier (and thus virtual thread) is "frozen" with 
regards to any transition. It could be anywhere in the process of 
mounting/unmounting (depending of course exactly where the carrier might 
respond to the handshake request), and the actual handshake operation has to 
deal with that. But that is true no matter how you extracted a reference to the 
carrier. As I said before the only thing this change guarantees is that the 
carrier is protected by the TLH and can't fully terminate whilst handshaking 
with it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26287#discussion_r2229522833

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