[PAYARA-3860] - Added synchronization block double check to avoid race condition #4021
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cubastanley
changed the title
|
Jenkins test please |
pdudits
approved these changes
Jun 7, 2019
Pandrex247
requested changes
Jun 7, 2019
| if (me == null) {//race check | ||
| initialiseInstanceDescriptor(); | ||
| //Race condition double check | ||
| if (me == null) { |
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https://en.wikipedia.org/wiki/Double-checked_locking#Usage_in_Java
https://www.javaworld.com/article/2074979/double-checked-locking--clever--but-broken.html
Page 348 of the book I'm about to plonk on your desk :)
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Oh, why did I miss that article? :)
Likely the easiest solution then is to replace any access to me with synchronized getter that can also initialize the descriptor when null.
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Is something like
private synchronized InstanceDescriptorImpl getMyInstanceDescriptor() {
if(me == null) {
initialiseInstanceDescriptor();
}
return me;
}
the kind of thing you mean?
|
Jenkins test please |
pdudits
approved these changes
Jun 10, 2019
| @Inject | ||
| private PayaraExecutorService executor; | ||
|
|
||
| private synchronized InstanceDescriptorImpl getMyInstanceDescriptor() { | ||
| if(me == null) { |
| @@ -239,50 +243,46 @@ void postConstruct() { | |||
| @SuppressWarnings({"unchecked"}) | |||
| public void event(Event event) { | |||
| if (event.is(EventTypes.SERVER_READY)) { | |||
| initialiseInstanceDescriptor(); | |||
| PayaraInternalEvent pie = new PayaraInternalEvent(PayaraInternalEvent.MESSAGE.ADDED, me); | |||
| //initialiseInstanceDescriptor(); | |||
Pandrex247
approved these changes
Jun 10, 2019
|
Jenkins Test Please |
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Added a synchronized double check in PayaraInstanceImpl to avoid race condition - tested through sheer brute forcing of Thread.sleep() and spamming of functionality and problem no longer appears to be present