Re: 8218401: WRONG_PHASE: vmTestbase/nsk/jvmti test crash

[serguei.spit...@oracle.com]

Hi Daniil,

No chance for it if you lock a raw monitor in the event callbacks.

Thanks,
Serguei

On 3/20/19 14:58, Daniil Titov wrote:

Hi Serguei,

I think that just disabling event notifications inside VMDeath callback still 
leaves a small window for VMDeath callback being called after the classload 
callback is called (or about being called)  but before it enters a raw monitor. 
Thus I decided to follow your original suggestion  and restore volatile 
modifier for callbacksEnabled.  Please review a new version of the patch.

Webrev: http://cr.openjdk.java.net/~dtitov/8218401/webrev.03/
Bug : https://bugs.openjdk.java.net/browse/JDK-8218401

Thanks!

Best regards,
Daniil



From: <serguei.spit...@oracle.com>
Organization: Oracle Corporation
Date: Tuesday, March 19, 2019 at 7:17 PM
To: Daniil Titov <daniil.x.ti...@oracle.com>, OpenJDK Serviceability 
<serviceability-dev@openjdk.java.net>, Jean Christophe Beyler <jcbey...@google.com>
Subject: Re: 8218401: WRONG_PHASE: vmTestbase/nsk/jvmti test crash

Hi Daniil,

I'd keep the volatile modifier for callbacksEnabled to disable compiler 
optimizations.
Otherwise, looks good to me.


Another approach could be to disable event notifications in VMDeath callback 
with:
   SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_CLASS_LOAD, NULL);
   SetEventNotificationMode(JVMTI_DISABLE, JVMTI_EVENT_BREAKPOINT, NULL);
   . . .

Thanks,
Serguei

On 3/18/19 6:58 PM, Daniil Titov wrote:
Hi Serguei and JC,

Please review a new version of the fix that locks a monitor across the 
callbacks, as Serguei suggested.

Webrev: http://cr.openjdk.java.net/~dtitov/8218401/webrev.02/
Bug: https://bugs.openjdk.java.net/browse/JDK-8218401

Thanks!
--Daniil


On 3/18/19, 9:47 AM, mailto:serguei.spit...@oracle.com 
mailto:serguei.spit...@oracle.com wrote:

     Hi Daniil,

The JVMTI phase can change in the middle of callback work after the

     check you added.
     I'd suggest to lock a raw monitor across the callbacks to make them atomic.

Thank you for taking care about this issue! Thanks,

     Serguei

On 3/15/19 16:08, Daniil Titov wrote:

     > Please review the change that fixes 3 tests that intermittently fail 
with JVMTI_ERROR_WRONG_PHASE error.
     >
     > The problem here is that the callbacks these tests enable keep 
processing events and perform JVMTI calls after VM is terminated. The fix makes 
these test listen for VMDeath event and  quick return from the callbacks after 
VMDeath event is received.
     >
     > Webrev: http://cr.openjdk.java.net/~dtitov/8218401/webrev.01/
     > Bug: https://bugs.openjdk.java.net/browse/JDK-8218401
     >
     > Thanks!
     > -Daniil
     >
     >