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Revert unnecessary changes to VM shutdown #10328

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merged 2 commits into from
Aug 4, 2020
Merged

Revert unnecessary changes to VM shutdown #10328

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3003ce6
Revert "Close timing hole in System.exit"
gacholio Jul 29, 2020
a0b599c
Revert "Allow System.exit from finalizer during DestroyJavaVM"
gacholio Jul 29, 2020
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38 changes: 10 additions & 28 deletions runtime/vm/jniinv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1084,38 +1084,20 @@ jint JNICALL AttachCurrentThreadAsDaemon(JavaVM * vm, void ** p_env, void * thr_

#if (defined(J9VM_OPT_SIDECAR))
/* run the shutdown method in java.lang.Shutdown */
void sidecarShutdown(J9VMThread* shutdownThread)
{
void sidecarShutdown(J9VMThread* shutdownThread) {
J9JavaVM * vm = shutdownThread->javaVM;
omrthread_monitor_t mutex = vm->runtimeFlagsMutex;
J9NameAndSignature nas;

nas.name = (J9UTF8*)&j9_shutdown;
nas.signature = (J9UTF8*)&j9_void_void;

/* Set a flag to allow System.exit to run from within finalizers run by the shutdown code */

if (NULL != mutex) {
omrthread_monitor_enter(mutex);
}
vm->runtimeFlags |= J9_RUNTIME_CLEANUP;
if (NULL != mutex) {
omrthread_monitor_exit(mutex);
}

enterVMFromJNI(shutdownThread);
runStaticMethod(shutdownThread, (U_8*)"java/lang/Shutdown", &nas, 0, NULL);
internalExceptionDescribe(shutdownThread);
releaseVMAccess(shutdownThread);
if (!(vm->runtimeFlags & J9_RUNTIME_CLEANUP)) {
J9NameAndSignature nas;

/* Unset the flag so System.exit is no longer allowed (particularly while the VMDeath JMVTI event is in progress) */
nas.name = (J9UTF8*)&j9_shutdown;
nas.signature = (J9UTF8*)&j9_void_void;

if (NULL != mutex) {
omrthread_monitor_enter(mutex);
}
vm->runtimeFlags &= ~J9_RUNTIME_CLEANUP;
if (NULL != mutex) {
omrthread_monitor_exit(mutex);
vm->runtimeFlags |= J9_RUNTIME_CLEANUP;
enterVMFromJNI(shutdownThread);
runStaticMethod(shutdownThread, (U_8*)"java/lang/Shutdown", &nas, 0, NULL);
internalExceptionDescribe(shutdownThread);
releaseVMAccess(shutdownThread);
}
}
#endif /* J9VM_OPT_SIDECAR */
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41 changes: 14 additions & 27 deletions runtime/vm/jvminit.c
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Expand Up @@ -492,7 +492,6 @@ void OMRNORETURN exitJavaVM(J9VMThread * vmThread, IDATA rc)

if (vm != NULL) {
PORT_ACCESS_FROM_JAVAVM(vm);
omrthread_monitor_t mutex = vm->runtimeFlagsMutex;

#if defined(J9VM_INTERP_ATOMIC_FREE_JNI)
/* exitJavaVM is always called from a JNI context */
Expand All @@ -502,40 +501,28 @@ void OMRNORETURN exitJavaVM(J9VMThread * vmThread, IDATA rc)

/* we only let the shutdown code run once */

if (NULL != mutex) {
omrthread_monitor_enter(mutex);
if(vm->runtimeFlagsMutex != NULL) {
omrthread_monitor_enter(vm->runtimeFlagsMutex);
}

if (J9_ARE_ANY_BITS_SET(vm->runtimeFlags, J9_RUNTIME_EXIT_STARTED)) {
/* CLEANUP indicates that the VM is running the exit hooks/finalizers
* on exit - exit must be allowed in this case, but only from a finalizer
* thread (for simplicity, just check for a system thread as no other
* VM-owned threads will be attempting exit).
*
* CLEANUP will only ever be set once EXIT_STARTED has been set,
* so setting the `J9_RUNTIME_EXIT_STARTED` flag again below is harmless.
*/
if (J9_ARE_NO_BITS_SET(vmThread->privateFlags, J9_PRIVATE_FLAGS_SYSTEM_THREAD)
|| J9_ARE_NO_BITS_SET(vm->runtimeFlags, J9_RUNTIME_CLEANUP)
) {
if (NULL != mutex) {
omrthread_monitor_exit(mutex);
}
if(vm->runtimeFlags & J9_RUNTIME_EXIT_STARTED) {
if (vm->runtimeFlagsMutex != NULL) {
omrthread_monitor_exit(vm->runtimeFlagsMutex);
}

if (vmThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
internalReleaseVMAccess(vmThread);
}
if (vmThread->publicFlags & J9_PUBLIC_FLAGS_VM_ACCESS) {
internalReleaseVMAccess(vmThread);
}

/* Do nothing. Wait for the process to exit. */
while (1) {
omrthread_suspend();
}
/* Do nothing. Wait for the process to exit. */
while (1) {
omrthread_suspend();
}
}

vm->runtimeFlags |= J9_RUNTIME_EXIT_STARTED;
if (NULL != mutex) {
omrthread_monitor_exit(mutex);
if(vm->runtimeFlagsMutex != NULL) {
omrthread_monitor_exit(vm->runtimeFlagsMutex);
}

#ifdef J9VM_OPT_SIDECAR
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