Hi Martin,
On 02/14/2018 10:58 AM, Peter Levart wrote:
I take back this claim. Of course the the following race is possible:
- Thread1: calls runAllFinalizers and takes a Finalizer from
'unprocessed' list.
- Thread2: takee the same Finalizer instance from ReferenceQueue and
calls runFinalizer()
- Thread1: calls runFinalizer() with the same instance for the 2nd
time now.
... but this could be "fixed" if the taking of next Finalizer from
'unfinalized' list and removing it from the same list was a single
atomic operation. What do you say of the following further simplification:
http://cr.openjdk.java.net/~plevart/jdk-dev/8197812_Data_race_in_Finalizer/webrev.01/
Regards, Peter
Regards, Peter
On 02/14/2018 10:39 AM, Peter Levart wrote:
I could even claim that simplifying the if statement in remove() to:
if (unfinalized == this) {
unfinalized = this.next;
}
makes checking for hasBeenFinalized() in runFinalizer() redundant as
it would not be possible for runFinalizer() to be called more than
once for each Finalizer instance because:
- ReferenceQueue never returns the same Reference instance twice or
more times.
- 'unfinalized' will never point back to the same Finalizer instance
for the 2nd time, because it always "travels" in the forward
direction (unfinalized = unfinalized.next).
Regards, Peter
(I rest now).
