> This fix is for JDK 23 but the intention is to back port it to 22 in RDP-1 > time frame. > It is fixing a deadlock issue between `VirtualThread` class critical sections > with the `interruptLock` (in methods: `unpark()`, `interrupt()`, > `getAndClearInterrupt()`, `threadState()`, `toString()`), > `JvmtiVTMSTransitionDisabler` and JVMTI `Suspend/Resume` mechanisms. > The deadlocking scenario is well described by Patricio in a bug report > comment. > In simple words, a virtual thread should not be suspended during > 'interruptLock' critical sections. > > The fix is to record that a virtual thread is in a critical section > (`JavaThread`'s `_in_critical_section` bit) by notifying the VM/JVMTI about > begin/end of critical section. > This bit is used in `HandshakeState::get_op_for_self()` to filter out any > `HandshakeOperation` if a target `JavaThread` is in a critical section. > > Some of new notifications with `notifyJvmtiSync()` method is on a performance > critical path. It is why this method has been intrincified. > > New test was developed by Patricio: > `test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendWithInterruptLock` > The test is very nice as it reliably in 100% reproduces the deadlock without > the fix. > The test is never failing with this fix. > > Testing: > - tested with newly added test: > `test/hotspot/jtreg/serviceability/jvmti/vthread/SuspendWithInterruptLock` > - tested with mach5 tiers 1-6
Serguei Spitsyn has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 10 commits: - Merge - review: improve an assert message - review: moved a couple of comments out of try blocks - review: moved notifyJvmtiDisableSuspend(true) out of try-block - review: 1) replace CriticalLock with DisableSuspend; 2) minor tweaks - review: (1) rename notifyJvmti method; (2) add try-final statements to VirtualThread methods - Resolved merge conflict in VirtualThread.java - added @summary to new test SuspendWithInterruptLock.java - add new test SuspendWithInterruptLock.java - 8311218: fatal error: stuck in JvmtiVTMSTransitionDisabler::VTMS_transition_disable ------------- Changes: https://git.openjdk.org/jdk/pull/17011/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17011&range=07 Stats: 229 lines in 15 files changed: 196 ins; 0 del; 33 mod Patch: https://git.openjdk.org/jdk/pull/17011.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/17011/head:pull/17011 PR: https://git.openjdk.org/jdk/pull/17011
