[prev in list] [next in list] [prev in thread] [next in thread] 

List:       openjdk-serviceability-dev
Subject:    Re: 12 RFR(M) 8195635: [Graal] nsk/jvmti/unit/ForceEarlyReturn/earlyretbase crashes with assertion
From:       dean.long () oracle ! com
Date:       2019-01-30 2:32:06
Message-ID: c26922ac-bdef-15bc-0e3b-abc6b24d6824 () oracle ! com
[Download RAW message or body]

I'm withdrawing this RFR for 12.

dl

On 1/28/19 5:13 PM, dean.long@oracle.com wrote:
> http://cr.openjdk.java.net/~dlong/8195635/webrev.5/
> https://bugs.openjdk.java.net/browse/JDK-8195635
>
> Please see the bug report for all the gory details.   Here's the short 
> version:
>
> If we allow any safepoint to be a suspend point, we run into trouble 
> with PopFrame and ForceEarlyReturn, which reasonably expect the top 
> frame not to change between the suspend and when the 
> PopFrame/ForceEarlyReturn is executed.   Normally this is not an issue, 
> but certain safepoints cause problems, when we are about to call a new 
> Java method.   In particular, if we safepoint and suspend in 
> JavaCallWrapper, the top frame will still be the caller, but when we 
> execute the PopFrame/ForceEarlyReturn we will be in the callee.
>
> The solution this patch takes is to block suspend around troublesome 
> VM code using a new "allow_suspend" thread flag.   This means 
> JavaThread::java_suspend can't just ask the VMThread to safepoint and 
> be done.   Instead it has wait and allow threads to roll forward to an 
> allowed suspend point.
>
> dl

[prev in list] [next in list] [prev in thread] [next in thread]