[8u] JDK-8191393: Random crashes during cfree+0x1c

[Hohensee, Paul]

Np sponsoring your patch. I've also added a Fix Request comment to the JBS issue.

Paul

On 4/8/20, 12:36 PM, "Liu, Xin" <xxinliu at amazon.com> wrote:

    Hi, Reviewers, 
    
    Thanks for reviewing. 
    
    Here is the modified webrev: https://cr.openjdk.java.net/~xliu/8191393/02/webrev/
    @Paul, Could you sponsor this webrev? 
    I add the label "jdk8u-fix-request"  to JDK-8191393.
    
    Thanks, 
    --lx
    
    
    
     
    https://bugs.openjdk.java.net/browse/On 4/8/20, 9:13 AM, "Andrew Dinn" <adinn at redhat.com> wrote:
    
        CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe.
        
        
        
        On 08/04/2020 16:50, Hohensee, Paul wrote:
        > Looks good now, except one more small issue.
        >
        > I forgot to say before that, given that rotate_log and write are now synchronized, the rotate_log method comment is inaccurate. It could be changed to eliminate the reference to 8191393 and read something like
        >
        >     // rotate_log must be called from the VMThread at a safepoint. In case of need to do
        >     // gc log rotation from a thread other than the VMThread, a subtype of VM_Operation
        >     // should be created and be submitted to the VMThread's operation queue. DO NOT call this
        >     // function directly. It is safe to rotate the log at a safepoint via the VMThread because
        >     // no mutator threads run concurrently with the VMThread, and GC threads that run
        >     // concurrently with the VMThread are synchronized in write and rotate_log via _file_lock.
        >     // rotate_log can write log entries, so write does a recursive lock check on _file_lock.
        Yes, that's very clear. Still ok for me assuming the above change. No
        need for another webrev.
        
        regards,
        
        
        Andrew Dinn
        -----------
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        Red Hat UK Ltd
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