Does this look like a race?
aph at redhat.com
Wed Aug 13 09:05:56 UTC 2014
On 08/13/2014 08:55 AM, David Holmes wrote:
> On 13/08/2014 1:01 AM, Andrew Haley wrote:
>> (Please forgive me if this should go to the AWT list or somesuch. It
>> seems to me like this is not really a graphics-related issue, but one
>> of Java concurrency.)
>> This is in JDK9, sun.font.GlyphList. There is a non-volatile boolean
>> inUse, and it is not always written in a synchronized block. It is
>> used to allow exclusive access to a singleton instance.
>> It seems to me that, at a minimum, inUse should be volatile, or e.g.
>> strikelist might be overwritten to null after some other thread has
>> started using this GlyphList. Do you agree?
> Yes, either inUse needs to be volatile and used in a way that ensures
> the correct happens-before relationships, or dispose() needs to do all
> modifications to the shared instance inside a synchronized block and
> clear inUse in that block.
Yes, I thought so. There are probably a dozen ways of doing this
correctly, but this way is certainly wrong.
JDK-8054991 - sun.font.GlyphList uses broken double-checked locking
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