Bug 74173

Summary:	ddcprobe can trigger a kernel panic
Product:	[Retired] Red Hat Linux	Reporter:	Bob Dowling <rjd4>
Component:	XFree86	Assignee:	Dave Jones <davej>
Status:	CLOSED WONTFIX	QA Contact:	Brian Brock <bbrock>
Severity:	high	Docs Contact:
Priority:	medium
Version:	7.3	CC:	pfrields
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
URL:	http://www-uxsup.csx.cam.ac.uk/~rjd4/bugs/kernel1/
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2004-11-27 23:12:37 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Bob Dowling 2002-09-17 11:08:05 UTC

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20020809

Description of problem:
On a small number of our systems, the ddcprobe command causes a kernel panic. 
It doesn't happen always and only some systems exhibit this behaviour.

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


How reproducible:
Sometimes

Steps to Reproduce:
1.Run ddcprobe many times (eg in a loop of "ddcprobe; sleep 5")
2.That's it!
3.
	

Actual Results:  We get a few lines of identical ddcprobe output and then the
kernel panics.

Expected Results:  We should have just seen large number of identical DDC lines.

Additional info:

At the URL quotes you can find our manual transcription of the screen contining
the kernel panic message, the output of a run of ddcprobe and the hardware
configuration as spotted by kudzu.

$ rpm -q kernel
kernel-2.4.18-7.80
$ rpm -qf /usr/sbin/kudzu 
kudzu-0.99.63-3
$ rpm -qf /usr/sbin/ddcprobe 
rhpl-0.30-1

Comment 1 Arjan van de Ven 2002-09-17 11:31:07 UTC

please try a more recent kernel too; we've fixed quite a few bugs in the vm86
emulation code (and ddcprobe uses that a lot ;)

Comment 2 Bob Dowling 2002-09-18 14:02:24 UTC

We have tried it again with kernel-2.4.18-11 and the problem occurs in exactly
the same way.  This is the latest in our "null" mirror.  If you had a different
kernel in mind please give specifics.

Comment 3 Bob Dowling 2002-09-18 14:11:44 UTC

Further data: We have built kernel-2.4.18-7.80 with apm configured as a module.
 With the module unloaded our kernel survives ddcprobe without difficulty. 
Loading the module causes the crashes to recur.

Comment 4 Mike McLean 2003-01-02 19:01:39 UTC

This bug has been inappropriately marked MODIFIED. Please review the bug life
cycle information at 
http://bugzilla.redhat.com/bugzilla/bug_status.cgi

Changing bug status to ASSIGNED.