Bug 69198

Summary: IBM 1.3.1 JDK does not run on AS/7.2 SMP
Product: Red Hat Enterprise Linux 2.1 Reporter: Bryan Che <bche>
Component: glibcAssignee: Jakub Jelinek <jakub>
Status: CLOSED CURRENTRELEASE QA Contact: Brian Brock <bbrock>
Severity: high Docs Contact:
Priority: high    
Version: 2.1CC: anderson, bennet, bstevens, fweimer, lwoodman, richardl, shillman
Target Milestone: ---   
Target Release: ---   
Hardware: i686   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2003-07-25 15:23:20 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Flags
This software will reproduce the JDK error using ant none

Description Bryan Che 2002-07-18 20:11:59 UTC 
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020606

Description of problem:
The IBM 1.3.1 JDK that ships with Advanced Server freezes on 7.2 and Advanced
Server SMP machines.  It runs fine on 7.2 and AS single-processor machines. 
Additionally, the JDK runs fine on 7.3 SMP and single-processor machines.

I have a dual-cpu box with 7.2.  This box has glibc-2.2.4-24 on it and also the
2.4.9-31smp kernel.

When I run a java process on the box, the java process freezes.

I found a discussion at
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=acad4i%241coq%241%40news.boulder.ibm.com
that suggested trying to set the LD_ASSUME_KERNEL=2.2.5 environment variable to
address this issue.

When I set this parameter, the java process will run and not freeze. However,
the JDK performance is extremely slow when I set this parameter.  Additionally,
I will see sporadic defunct Java processes remaining after I stop running Java.
 I do not see this behaviour with the 1.3.1 JDK on 7.3 SMP.

One other thing that I have tried is to replace the 2.4.9-31smp kernel on the
7.2 box with a 2.4.18-5smp kernel from a 7.3 box.  With this kernel, Java will
run without the LD_ASSUMER_KERNEL=2.2.5 parameter set.  However, it is still slow.

So, there seems to be some glibc bug in 7.2/AS that prevents the JDK from
running on smp boxes.  The 2.4.9-based SMP kernels with this glibc cause Java to
freeze unless the LD_ASSUME_KERNEL=2.2.5 parameter is set.  The 2.4.18-based
kernels somehow do not freeze with this glibc, but performance is still
extremely slow. 

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1. run a Java program with the IBM 1.3.1 JDK

Actual Results:  The Java process freezes

Expected Results:  It should run

Additional info:
Comment 1 Bryan Che 2002-07-19 18:06:17 UTC 
Created attachment 66025 [details]
This software will reproduce the JDK error using ant
Comment 2 David Edwards 2002-07-22 10:37:26 UTC 
The Read Me for the IBM Java SDK 1.3.1 states firmly that the environment 
variable LD_ASSUME_KERNEL must be set for SMP operation. I have included the 
relevant section below. This explains the "freeze" behaviour described in this 
bugzilla.

The technical justification for this restriction is as follows:-
On Intel, there is a kernel bug such that registers can be corrupted when we 
switch context on an SMP. This is fixed in the 2.4.10 kernel. This affects the 
JIT such that we have to use an alternate method to store a pointer to our 
ExecEnv but, this alternate method doesnt work if Linux is using floating 
stacks. Thus, if you are on an IA32 SMP with floating stacks (eg RedHat) with a 
2.4.0-2.4.9 kernel you have to turn off floating stacks using an environment 
variable.

The extract from the Read Me is:-
Working with floating stacks
Certain Linux distributions - Red Hat, for example - have enabled a GLIBC 
feature called 'floating stacks'. Because of Linux kernel limitations, the JVM 
will not run on SMP hardware with floating stacks enabled if the kernel level 
is less than 2.4.10. In this environment, floating stacks must be disabled 
before the JVM, or any application that starts the JVM, is started. On Red Hat, 
you disable floating stacks by exporting an environment variable, thus:

export LD_ASSUME_KERNEL=2.2.5
On a non-floating stack Linux system, regardless of what is set for -Xss, a 
minimum native stack size of 256KB for each thread is provided. On a floating 
stack Linux system, the -Xss values are honored. Thus, if you are migrating 
from a non-floating stack Linux system, you must ensure that any -Xss values 
are large enough and are not relying on a minimum of 256KB.
Comment 3 Jakub Jelinek 2002-07-23 19:17:36 UTC 
This readme is inaccurate, since it was not 2.4.10 where the LDT SMP problems
were fixed, but 2.4.8 AFAIK.
Comment 4 Suzanne Hillman 2003-07-25 14:38:53 UTC 
This has not been updated in over a year. Is this still a problem since the most
recent Quartly Update (QU2)?
Comment 5 Richard Li 2003-07-25 14:42:48 UTC 
Someone (Jakub?) fixed the glibc bug and it was pushed out at least six months
ago. We're not seeing this bug on our AS2.1 SMP machines any more.
Comment 6 Suzanne Hillman 2003-07-25 15:23:20 UTC 
As per comment #5, closing as resolved in CURRENTRELEASE.