[9] RFR(S): 8152947: VM crash with assert(!removed || is_in_use()) failed: unused osr nmethod should be invalidated

[Tobias Hartmann]

Hi Vladimir,

On 29.03.2016 17:42, Vladimir Ivanov wrote:
> Does it still work when method() == NULL?
> 
> +#ifdef ASSERT
> +    // Make sure osr nmethod is invalidated, i.e. not on the list
> +    bool found = method()->method_holder()->remove_osr_nmethod(this);
> +    assert(!found, "osr nmethod should have been invalidated");
> +#endif

Yes, you are right. We should check for method() != NULL. New webrev:
http://cr.openjdk.java.net/~thartmann/8152947/webrev.01

Thanks,
Tobias

> 
> Best regards,
> Vladimir Ivanov
> 
> On 3/29/16 6:28 PM, Tobias Hartmann wrote:
>> Hi Dmitry,
>>
>> On 29.03.2016 15:05, Dmitry Dmitriev wrote:
>>> Hi Tobias,
>>>
>>> I think that "#ifdef ASSERT" must be instead of "#ifndef ASSERT" on lines 1338 and 1516. And it seems that the whole fix should be retested in this case.
>>
>> Oh, thanks for catching this!
>>
>> Here is the new webrev:
>> http://cr.openjdk.java.net/~thartmann/8152947/webrev.01
>>
>> I verified that this (still) fixes the problem and re-submitted the tests.
>>
>> Thanks,
>> Tobias
>>
>>>
>>> Thanks,
>>> Dmitry
>>>
>>> On 29.03.2016 15:01, Tobias Hartmann wrote:
>>>> Hi,
>>>>
>>>> please review the following patch:
>>>>
>>>> https://bugs.openjdk.java.net/browse/JDK-8152947
>>>> http://cr.openjdk.java.net/~thartmann/8152947/webrev.00/
>>>>
>>>> JDK-8023191 added an assert to check if osr nmethods are invalidated (i.e. removed from the osr list). The assert is too strong because nmethod::invalidate_osr_method() may be executed by multiple threads that compete for making an osr nmethod not-entrant:
>>>>
>>>> Thread 1: Invalidates the osr nmethod and blocks just before executing the assert in line 1397.
>>>> Thread 2: nmethod is already invalidated. Acquires patching lock and sets the nmethod to not-entrant.
>>>> Thread 1: Continues execution and hits the assert because the nmethod was on the list and is (now) not-entrant.
>>>>
>>>> Thread 1 should ignore this and return. See also comment in nmethod::make_not_entrant_or_zombie():
>>>>     // another thread already performed this transition so nothing
>>>>     // to do, but return false to indicate this.
>>>>
>>>> I changed the verification code to check for osr invalidation *after* the state of the nmethod was set.
>>>>
>>>> Tested with failing test, JPRT and RBT (in progress).
>>>>
>>>> Thanks,
>>>> Tobias
>>>