From owner-freebsd-hackers  Thu Nov 15  6: 8:19 2001
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From: "Koster, K.J." <K.J.Koster@kpn.com>
To: 'Andrew Atrens' <atrens@nortelnetworks.com>,
	"FreeBSD Java mailing list (E-mail)" <freebsd-java@freebsd.org>
Cc: hackers@FreeBSD.ORG
Subject: RE: linux JVMs not handling SEGV well.
Date: Thu, 15 Nov 2001 15:08:07 +0100
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[ CC'd to freebsd-java, please followup there too ]

Dear Andrew,

This question is better asked on -java, so I forwarded you question. There
are many hardcore JVM hackers on that list.

> 
> I'm using 4.x-stable, linux-base-6.x, and am encountering a lot of
> turbulence with both Sun's jdk1.3.x HotSpot JVM and IBM's 
> linux jdk1.3.x JVM.
>
Well, considering that technically we don't actually have any Java VM post
1.1.8... :-)

>
> I have a buggy 3rdparty java app that occasionally causes a 
> null pointer
> exception to be thrown. While not fatal for the app (the exception is
> correctly caught), it's most often fatal for the JVM. The SUN 
> jvm SEGV's (
> doesn't correctly catch the SIGNAL ), while the IBM jvm seems to get
> locked in kernel mode - only responding to SIGKILL and 
> chewing up tons of
> 'system' cpu time. The common denominator here is that both 
> JITs utilize
> linux threads. When I use a non-threaded JIT, the problem 
> doesn't occur.
>
> The problem is readily reproducible, but I'm not sure how to debug it.
> I've played with truss and ktrace, but I think it's time to 
> begin thinking
> about using the kernel debugger.
> 
Could you perhaps provide a simple code sample that allows us to reproduce
the problem?

    Kees Jan

================================================
 You are only young once,
       but you can stay immature all your life.

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