(0.43) Fix GetThreadStateTest #18661
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VirtualThreads.park performs operations in the below order: Set VThreadInspector to -1 and then acquire vmThreadListMutex JVMTI GetThreadState -> ... -> getVMThread follows the below order: Acquire vmThreadListMutex and then spin until VThreadInspector != -1 A deadlock occurs because the order of operations is inconsistent between VirtualThreads.park and JVMTI GetThreadState. To resolve the deadlock, the operations in getVMThread are swapped to match the operations in VirtualThreads.park: Acquire VThreadInspector and then acquire vmThreadListMutex Related: eclipse-openj9#18642 Signed-off-by: Babneet Singh <[email protected]>
RI and JTReg tests expect the same JVMTI thread state for - PARKED and PINNED - TIMED_PARKED and TIMED_PINNED Related: eclipse-openj9#18642 Signed-off-by: Babneet Singh <[email protected]>
pshipton
approved these changes
Dec 20, 2023
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Acquire VThreadInspector before vmThreadListMutex to avoid deadlock
VirtualThreads.parkperforms operations in the below order:Set
VThreadInspectorto-1and then acquirevmThreadListMutexJVMTI GetThreadState -> ... -> getVMThreadfollows the below order:Acquire
vmThreadListMutexand then spin untilVThreadInspector != -1A deadlock occurs because the order of operations is inconsistent
between
VirtualThreads.parkandJVMTI GetThreadState.To resolve the deadlock, the operations in
getVMThreadare swappedto match the operations in
VirtualThreads.park:Acquire
VThreadInspectorand then acquirevmThreadListMutexVirtualThread State: *PINNED is identical to *PARKED
RI and JTReg tests expect the same JVMTI thread state for
PARKEDandPINNEDTIMED_PARKEDandTIMED_PINNEDRelated: #18642
Port of #18660 for 0.43
Signed-off-by: Babneet Singh [email protected]