Possible subtle memory model error in ClassValue
galder at redhat.com
Wed Aug 19 13:12:54 UTC 2020
On Mon, Aug 10, 2020 at 2:19 PM Doug Lea <dl at cs.oswego.edu> wrote:
> Catching up...
> As implied in other posts, the minimal fix is to add a trailing release
> fence (using Unsafe?) to the constructor.
FYI I have sent an RFR with the proposed fix ^
> Or less delicately, to access
> only using acquire/release (which will cost a bit on ARM/Power, but
> probably not noticeable on x86), or most simply (but expensively) to
> declare the field volatile.
> Also, as Hans noted, the consensus seems to be that there not enough to
> be gained by always adding a release fence to constructors. A few errors
> like this might never occur, but other related anomalies with non-final
> field accesses would remain.
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