On Wed, 17 Dec 2025 08:14:41 GMT, Serguei Spitsyn <[email protected]> wrote:
>> An asynchronous handshake operation (`ThreadSelfSuspensionHandshakeClosure`) >> can be installed when the target thread is not in a `MountUnmountDisabler` >> scope. But the target thread can enter such scope by the time the operation >> is self-processed by the target thread. >> >> This is fixed by a small tweak in the function >> `HandshakeOperation* HandshakeState::get_op_for_self(bool allow_suspend, >> bool check_async_exception)`. >> The tweak is to skip a `HandshakeOperation` if >> `_handshakee->is_vthread_transition_disabler() == true`, so the same >> temporary suspension disabling mechanism would be used as for >> `_handshakee->is_disable_suspend() == true`. >> >> All other changes are to move the `is_vthread_transition_disabler()` out of >> DEBUG to product. >> >> Testing: >> - In progress: mach5 tiers 1-6 > > Serguei Spitsyn has updated the pull request incrementally with one > additional commit since the last revision: > > review: replace fix with just one assert I think better replaces text with something non-TMP. Also, might be worth add comment for ThreadSelfSuspensionHandshakeClosure somewhere. This comment should explain the connection of this ThreadSelfSuspension handshake and SuspendThreadHandshake. Ie there shouldn't safepoint between `SuspendResumeManager::suspend_with_handshake` and processing ThreadSelfSuspensionHandshake. It should help to understand why suspended thread thread can't be in disabler now. ------------- Marked as reviewed by lmesnik (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/28740#pullrequestreview-3588376322
