RFR: 8352178: Add precondition in VMThread::execute to prevent deadlock [v2]

[David Holmes]

On Tue, 18 Mar 2025 14:50:39 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/runtime/handshake.cpp line 359:
>> 
>>> 357:   // deadlock.
>>> 358:   assert(!current_thread->is_suspendible_thread(), "precondition");
>>> 359:   assert(!current_thread->is_indirectly_suspendible_thread(), "precondition");
>> 
>> Why not move the asserts to VMThread::execute() to cover any operation, not just VM_HandshakeAllThreads?
>
> Moved to `VMThread::execute` and edited the title.

Aren't Handshakes a superset of VMoperations? `VMThread::execute` will only affect VM_Operations, not direct Handshakes with other threads. Is the problem limited to a STS thread trying to execute a safepoint VM operation?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24088#discussion_r2004898247