RFR: 8215206: VtableStubs::find_stub is not appropriately protected by VtableStubs_lock

[Per Liden]

On 12/11/18 12:10 PM, Erik Österlund wrote:
> Hi,
> 
> In VtableStubs::find_stub we first perform a lookup in the table to 
> check for already created stubs under the VtableStubs_lock, then if not 
> found we create a new stub without the lock held, and then insert it 
> under the VtableStubs_lock without checking for entries inserted between 
> the lookup and insertion.
> If the VtableStubs_lock is to protect the table (which is the 
> intention), the lock should not be unlocked before lookup and insert.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8215206
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8215206/webrev.00/

Looks good to me.

cheers,
Per