RFR(one-liner): 8231321: compiler/codecache/stress/UnexpectedDeoptimizationAllTest.java failed assertion

[Robbin Ehn]

Hi Tobias,

On 9/25/19 10:58 AM, Tobias Hartmann wrote:
> Hi Robbin,
> 
> please note that we also hit the following assert (see comments in bug report):
> Crash: Internal Error ...nmethod.cpp...assert(!found) failed: osr nmethod should have been invalidated

Missed that one, I'll look into it.

Thanks, Robbin

> 
> Thanks,
> Tobias
> 
> On 25.09.19 10:12, Robbin Ehn wrote:
>> Hi all, please review.
>>
>> We no longer allow state to ever go backwards.
>> So trying to make a zombie not-entrant is fine.
>> What happens is something like:
>> - make not-entrant
>> - safepoint
>> - deopt all => start iteration over nmethods
>> - picks up this not-entrant method, since it is alive
>> - sweeper turns it into a zombie
>> - we try making the nmethod not-entrant once more => assert
>>
>> If we remove the assert the method would just returns false instead, which is expected.
>>
>> Thanks, Robbin
>>
>> Issue:
>> https://bugs.openjdk.java.net/browse/JDK-8231321
>>
>> Changeset:
>> diff -r 448fe2bfd505 src/hotspot/share/code/nmethod.cpp
>> --- a/src/hotspot/share/code/nmethod.cpp    Tue Sep 24 08:54:39 2019 +0200
>> +++ b/src/hotspot/share/code/nmethod.cpp    Wed Sep 25 10:02:45 2019 +0200
>> @@ -1288,17 +1288,16 @@
>>     }
>>   }
>>
>>   /**
>>    * Common functionality for both make_not_entrant and make_zombie
>>    */
>>   bool nmethod::make_not_entrant_or_zombie(int state) {
>>     assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");
>> -  assert(!is_zombie(), "should not already be a zombie");
>>
>>     if (Atomic::load(&_state) >= state) {
>>       // Avoid taking the lock if already in required state.
>>       // This is safe from races because the state is an end-state,
>>       // which the nmethod cannot back out of once entered.
>>       // No need for fencing either.
>>       return false;
>>     }