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

Dean Long dean.long at
Mon Jan 23 20:09:58 PST 2012

David, thanks for the review.  How many reviews do I need before I can 


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:
>> 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

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