RFR: 8214068: ZGC crashes with vmTestbase/nsk/jdi/ReferenceType/instances/instances004/TestDescription.java
per.liden at oracle.com
Wed Nov 21 10:10:39 UTC 2018
Thanks for reviewing Erik!
On 11/21/18 11:08 AM, Erik Österlund wrote:
> Hi Per,
> Looks good.
> On 2018-11-21 10:11, Per Liden wrote:
>> This patch adds a missing load barrier to the JVMTI heap walker. In
>> VM_HeapWalkOperation::collect_simple_roots() the SimpleRootsClosure
>> closure should not do raw loads of oops. Instead it should be loading
>> them using NativeAccess<AS_NO_KEEPALIVE>::oop_load().
>> This problem only affects ZGC, since it's (so far) the only collector
>> that scans JNIHandles concurrently.
>> The problem was easily reproducible when running
>> However, for some reason this isn't reproducing in our CI pipeline,
>> likely because of luck with timing. For example, this is harder to
>> reproduce in a scenario where your using a smaller heap and hence have
>> GC cycles happen more frequently.
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8214068
>> Webrev: http://cr.openjdk.java.net/~pliden/8214068/webrev.0
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