review request for 7130319: C2: running with -XX:+PrintOptoAssembly crashes the VM with assert(false) failed: bad tag in log

[Paul Hohensee]

You only need 1 Reviewer, the other doesn't have to be a Reviewer, but
does need an openjdk name.

Paul

On 1/23/12 11:13 PM, David Holmes wrote:
> On 24/01/2012 2:09 PM, Dean Long wrote:
>> David, thanks for the review. How many reviews do I need before I can
>> commit?
>
> Two. Though there seems to be some leeway as to whether both must be 
> Reviewers.
>
> David
>
>> dl
>>
>> On 1/23/2012 7:01 PM, David Holmes wrote:
>>> Looks good to me.
>>>
>>> David
>>>
>>> On 24/01/2012 5:25 AM, Dean Long wrote:
>>>> http://cr.openjdk.java.net/~dlong/7130319/webrev.00/
>>>>
>>>> The problem is that the VM thread is trying to exit while another
>>>> thread is writing to the XML log. The VM thread also wants to write
>>>> to the log, but notices the tag stack doesn't match up. A similar
>>>> problem came up before (6295565) and the solution was to relax the
>>>> assertion if we were shutting down through JNI DestroyJavaVM. The
>>>> above change follows that pattern and also allows shutdown
>>>> through JVM_Halt.
>>>>
>>>> More details thanks to David Holmes:
>>>>
>>>> "To be clear the VMThread is writing to the log (actually closing 
>>>> it) as
>>>> part of exit_globals() while executing VM_Exit::doit. This happens 
>>>> after
>>>> it calls set_vm_exited() so we add that as a guard against doing the
>>>> assertion. The problem arises because the CompilerThread was in the
>>>> middle of some writing (as part of PrintOptoAssembly) when it entered
>>>> the safepoint that allows the VM to exit."
>>>>
>>>> dl
>>>>
>>>>
>>>>
>>>>