RFR[9u-dev] 8130425: libjvm crash due to stack overflow in executables with 32k tbss/tdata

[David Holmes]

Hi Cheleswer,

On 13/01/2016 8:25 PM, cheleswer sahu wrote:
> Hi,
>
> Please review the code changes for
> "https://bugs.openjdk.java.net/browse/JDK-8130425".
>
> Problem summary: When a large TLS (Thread Local Storage) size is set for
> threads,  JVM is throwing StackOverflow exception.
>
> Problem Identified:
> As per investigation and a discussion we came to the conclusion that
> issue is not with the JVM but it lies in the way glibc has been
> implemented. When a TLS is declared , it steals the space from threads
> stack size.
> So if a thread is created with small stack size, and TLS is set to a
> large value, then it will result in StackOverflow. This is the exact
> case in this bug where reaper thread is allocated a very low stack size
> 32768.
>
> Discussion thread:
> http://mail.openjdk.java.net/pipermail/core-libs-dev/2015-December/037558.html
>
>
> Solution proposed:
> Its expected to get fix in glibc sometime , but for now I propose a
> workaround, a boolean system property "processReaperUseDefaultStackSize"

That might be a reasonable name for a -XX VM flag but system properties 
follow a more structured naming convention - possibly something like 
java.lang.Process.processReaperUsesDefaultStackSize? Though this is an 
implementation detail so maybe java.lang is not the right namespace for 
this either. Not sure who would know the best way to name this - 
probably core-libs folk. This would need to go through CCC process as well.

David
-----

> using which we can set the stack size for reaper thread to default
> instead of fix 32768. This property can be set by the user using "-D" or
> "System.setProperty()". I have tested this fix, it works well with TLS
> size between 32k to 128k.
>
> Fix:
> diff -r 5c4530bb9ae6
> src/java.base/share/classes/java/lang/ProcessHandleImpl.jav
> --- a/src/java.base/share/classes/java/lang/ProcessHandleImpl.java Fri
> Jan 08 13:06:29 2016 +0800
> +++ b/src/java.base/share/classes/java/lang/ProcessHandleImpl.java Tue
> Jan 12 15:55:50 2016 +0530
> @@ -83,9 +83,13 @@
>                   ThreadGroup systemThreadGroup = tg;
>
>                   ThreadFactory threadFactory = grimReaper -> {
> -                    // Our thread stack requirement is quite modest.
> -                    Thread t = new Thread(systemThreadGroup, grimReaper,
> -                            "process reaper", 32768);
> +                   Thread t = null;
> +                   if
> (Boolean.getBoolean("processReaperUseDefaultStackSize")) {
> +                       t = new Thread(systemThreadGroup, grimReaper,
> "process reaper");
> +                    } else {
> +                       // Our thread stack requirement is quite modest.
> +                       t = new Thread(systemThreadGroup, grimReaper,
> "process reaper", 32768);
> +                    }
>                       t.setDaemon(true);
>                       // A small attempt (probably futile) to avoid
> priority inversion
>                       t.setPriority(Thread.MAX_PRIORITY);
>
>
> Regards,
> Cheleswer