RFR (XS): 8062950: Bug in locking code when UseOptoBiasInlining is disabled: assert(dmw->is_neutral()) failed: invariant

Vladimir Kozlov vladimir.kozlov at oracle.com
Wed Nov 5 23:30:54 UTC 2014

It is our (Compiler group) code. This problem was introduced with my 
changes for RTM locking.

Martin your changes are good. But you cleanup a bit this code since we 
now never put markword to tmpReg before this call?


On 11/5/14 3:13 PM, Christian Thalinger wrote:
> I’m not exactly sure who is our biased locking expert these days but I guess it’s someone from the runtime team.  CC’ing them.
>> On Nov 5, 2014, at 7:38 AM, Doerr, Martin <martin.doerr at sap.com> wrote:
>> Hi,
>> we found a bug in MacroAssembler::fast_lock on x86 which shows up when UseOptoBiasInlining is switched off.
>> The problem is that biased_locking_enter is used with swap_reg_contains_mark==true, which is no longer correct after biased_locking_enter was put in front of check for IsInflated.
>> Please review
>> http://cr.openjdk.java.net/~goetz/webrevs/8062950-lockBug/webrev.00/ <http://cr.openjdk.java.net/~goetz/webrevs/8062950-lockBug/webrev.00/>
>> Best regards,
>> Martin

More information about the hotspot-compiler-dev mailing list