RFR: 8234509: Race in macOS os::processor_id()

[David Holmes]

Hi Erik,

Looks good. Good catch!

Thanks,
David

On 21/11/2019 7:15 pm, erik.osterlund at oracle.com wrote:
> Hi,
> 
> In os::processor_id() on macOS, a CAS protects initialization of 
> processor ID number given an APIC id. However, the CAS is not converted 
> properly to a boolean determining whether it succeeded or failed. The 
> implicit boolean conversion is wrong, allowing multiple threads to 
> increment the next processor ID. The result is that if another thread 
> runs on a different APIC id, we can get IDs that are higher than the 
> number of processors.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8234509
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8234509/webrev.00/
> 
> Thanks,
> /Erik