?
Solved

Pentium bug and Solaris 2.5.1 SMP

Posted on 1997-11-13
1
Medium Priority
?
329 Views
Last Modified: 2013-12-27
Hi,

some days before it was a discussion about Pentium bug
(lock cmpxchg8b qword ptrax -  F0 0F C7 C8) which hangs the machine.

I've tested it on several configurations and it is really very bad.

But what I'd like to know is why it happens on 2xPentium Solaris 2.5.1

I'm not a specialist in Solaris kernel and multitasking, but I have a
question which may be stupid.

If I execute the command I hang one of my two processors. Why the system
can't work on the rest one performing normal (or emergency) shutdown or
notifying sysadmin about the problem? Am I right that such a command is
executed only on one processor or not?

If yes then is it a bug in Solaris OS?

Is it a problem in Solaris or it is the problem of the SMP architecture on Intel platform (bus lock, etc.)?

Thanks in advance

Vitali

0
Comment
Question by:korostel
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 1

Accepted Solution

by:
Belar earned 100 total points
ID: 2007767
Well, to answer your first question. It happens on all pentium or pentium MMX. Pentium Pro and Pentium II are unaffected. For example it crashes my linux SMP so it is not OS related.

About your second answer, yes, indeed only one of the CPU is halted. It might be possible with the appropriate code for the second CPU to "reboot" the first. I actually saw a discussion about this exact issue in the linux-kernel mailing list. The only problem with this "fix" is that if an attacker just do : crash&crash&. It will hang both CPUs without giving time to them to reboot their peer. As for why, there is no notification that one of your cpu is halted. It is simple. I think Solaris or any other OS vendors didn't think it was possible to do such an event.

3) Solaris is not buggy. It is Intel that screwed up.

For more info on the bug go at www.x86.org (or is it com?) The exploit is pretty well documented there.
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In tuning file systems on the Solaris Operating System, changing some parameters of a file system usually destroys the data on it. For instance, changing the cache segment block size in the volume of a T3 requires that you delete the existing volu…
I have been running these systems for a few years now and I am just very happy with them.   I just wanted to share the manual that I have created for upgrades and other things.  Oooh yes! FreeBSD makes me happy (as a server), no maintenance and I al…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.
In a previous video, we went over how to export a DynamoDB table into Amazon S3.  In this video, we show how to load the export from S3 into a DynamoDB table.
Suggested Courses
Course of the Month9 days, 19 hours left to enroll

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question