[OpenJDK 2D-Dev] [8u] RFR JDK-8162461: Hang due to JNI up-call made whilst holding JNI critical lock.

Jayathirth D V jayathirth.d.v at oracle.com
Fri Sep 23 07:13:28 UTC 2016

Hi Phil,


I assumed setjmp/longjmp functions to be internal error handling mechanism rather than C standard library functions which provide non-local jumps.

I verified setjmp/longjmp usage in ImageIO JPEG context and we need that RELEASE_ARRAYS() call in writeImage() which I have removed.

Does I have to create a new Bug and add the RELEASE_ARRAY() call in writeImage() or I have to check-in this change under JDK-8162461 only? 


After check-in of this modification I will raise new webrev for 8u backport.




From: Philip Race 
Sent: Thursday, September 22, 2016 9:51 PM
To: Jayathirth D V
Cc: 2d-dev
Subject: Re: [OpenJDK 2D-Dev] [8u] RFR JDK-8162461: Hang due to JNI up-call made whilst holding JNI critical lock.


I see this is mostly what I approved for JDK9 but I noticed you made a change
after I approved it and I did not see or approve the updated version.
I am concerned about this comment you posted for the JDK 9 webrev :

>Regarding  "2856         RELEASE_ARRAYS(env, data, (const JOCTET *)(dest->next_output_byte));". 
>We don't need this RELEASE_ARRAY() call at this place as we have not yet pinned any buffer.
> So I have removed it.
>Please find updated webrev for review :

What makes you so sure we have not pinned a buffer by then ?
setjmp is special. It may return from any point in the writing process.

In other words that removal looks wrong to me.


On 9/15/16, 1:29 AM, Jayathirth D V wrote: 



Please review the following backport to JDK-8u from JDK-9 at your convenience:


JDK-9 review thread : http://mail.openjdk.java.net/pipermail/2d-dev/2016-September/007601.html 


Bug : https://bugs.openjdk.java.net/browse/JDK-8162461 


JDK-8u Webrev : HYPERLINK "http://cr.openjdk.java.net/%7Ejdv/8162461.8u/webrev.00/"http://cr.openjdk.java.net/~jdv/8162461.8u/webrev.00/ 


Issue : If we try to perform operations like reader.abort()/reader.dispose()/ reader.reset() in any of the IIOReadUpdateListener callbacks, JVM will throw deadlock error.


Root cause : We are making callbacks from native side to Java by holding some resources in JNI critical lock.


Solution : We have to release the JNI critical lock on the resources before we call Java function from native side. If we have JNI critical lock and we throw an Exception in that case also we should release the lock.


I have verified jtreg, JCK and JPRT in JDK8u-dev also.




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