RFR(XS): 8043070: nmethod::verify_interrupt_point() shouldn't enter safepoint

Igor Veresov igor.veresov at oracle.com
Wed May 14 07:39:58 UTC 2014


Mikael,

I agree it’s ugly and we have to rethink the code management locks, but it’s only dangerous if there is a safepoint-cooperating lock within the scope of this one. There isn’t any, so I assume it should be safe. Right?

igor
 
On May 14, 2014, at 12:04 AM, Mikael Gerdin <mikael.gerdin at oracle.com> wrote:

> Igor,
> 
> On Tuesday 13 May 2014 18.11.48 Igor Veresov wrote:
>> nmethod::verify_interrupt_point() is called from as part of nmethod
>> verification from ciEnv::register_method() that asserts no safepoint can
>> occur. However verify_interrupt_point() locks a mutex that may potentially
>> safepoint. A sample call stack of when it happens is in the following JBS
>> issue.
>> 
>> JBS: https://bugs.openjdk.java.net/browse/JDK-8043070
>> Webrev: http://cr.openjdk.java.net/~iveresov/8043070/webrev.00/
> 
> It's unsafe to mix safepoint-aware and safepoint-ignoring locking on a single 
> Mutex as that can deadlock the VM, see 
> https://bugs.openjdk.java.net/browse/JDK-8039458
> 
> CompiledIC_lock is taken without _no_safepoint_check_flag at all other uses.
> 
> /Mikael
> 
>> 
>> igor
> 



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