RFR: 8185529: JCK api/java_lang/Object/WaitTests failed with jdk10/hs nightly

[David Holmes]

Thanks Dan!

David

On 6/10/2017 11:58 PM, Daniel D. Daugherty wrote:
> Thumbs up!
> 
> Dan
> 
> 
> On 10/5/17 10:47 PM, David Holmes wrote:
>> Bug is not public - sorry.
>>
>> webrev: http://cr.openjdk.java.net/~dholmes/8185529/webrev/
>>
>> Also patch inline below.
>>
>> Problem: o.wait(Long.MAX_VALUE) returns immediately
>>
>> Cause: arithmetic overflow gives a time in the past so the timeout 
>> expires immediately
>>
>> This was introduced by the fix for:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8174231 "Factor out and share 
>> PlatformEvent and Parker code for POSIX systems."
>>
>> while we go to great lengths to ensure we avoid overflows inside the 
>> time calculation functions, I overlooked the fact that we now first 
>> convert a millisecond value into nanoseconds, which can overflow.
>>
>> Fix: limit the millis value to the existing hard limit of 
>> MAX_SECS*MILLIUNITS ms. That can not overflow when converted to nanos.
>>
>> Thanks,
>> David
>> -----
>>
>> --- old/src/hotspot/os/posix/os_posix.cpp    2017-10-06 
>> 00:34:31.595159338 -0400
>> +++ new/src/hotspot/os/posix/os_posix.cpp    2017-10-06 
>> 00:34:29.443037883 -0400
>> @@ -1770,6 +1770,12 @@
>>
>>    if (v == 0) { // Do this the hard way by blocking ...
>>      struct timespec abst;
>> +    // We have to watch for overflow when converting millis to nanos,
>> +    // but if millis is that large then we will end up limiting to
>> +    // MAX_SECS anyway, so just do that here.
>> +    if (millis / MILLIUNITS > MAX_SECS) {
>> +      millis = jlong(MAX_SECS) * MILLIUNITS;
>> +    }
>>      to_abstime(&abst, millis * (NANOUNITS / MILLIUNITS), false);
>