Bug 191989

Summary:	sending break to serial console hangs system
Product:	[Fedora] Fedora	Reporter:	Doug Chapman <dchapman>
Component:	kernel	Assignee:	Dave Jones <davej>
Status:	CLOSED RAWHIDE	QA Contact:	Brian Brock <bbrock>
Severity:	high	Docs Contact:
Priority:	high
Version:	rawhide	CC:	pfrields, wtogami
Target Milestone:	---	Keywords:	Reopened
Target Release:	---
Hardware:	ia64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2006-08-31 19:19:21 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:
Bug Depends On:
Bug Blocks:	163350

Description Doug Chapman 2006-05-16 18:03:24 UTC

Description of problem:
Serial consoles use "break" in place of the sysrq key.  Sending a break on my HP
Integrity servers via the remote console hangs the system to the point where the
system does not even respond to ping.  This makes it nearly impossible to debug
hang situations.

If the system is alive sending a character to /proc/sysrq-trigger still does
work OK so this appears to be a serial console issue rather than a sysrq issue.

Version-Release number of selected component (if applicable):
kernel-2.6.16-1.2203_FC6
(note, this is the first I have tried this on rawhide so I do not know when this
last worked)


How reproducible:
100%

Steps to Reproduce:
1. connect to an HP Integrity server via telnet to the MP
2. log in to the MP
3. type "co" to connect to the console
4. send a break using telnet: <ctrl>-] then "send break"

  
Actual results:
system hangs

Expected results:


Additional info:

Comment 1 Dave Jones 2006-06-23 04:06:10 UTC

I think this was due to the kgdb patches I was experimenting with.
It's likely this is fixed now, as they've been reverted.

Comment 2 Doug Chapman 2006-06-23 14:32:24 UTC

Appears that this is a different problem.  I am still seeing the hang on
2.6.16-1.2289_FC6.  Please let me know if there is something I can do to provide
more info that would be useful.

Comment 3 Doug Chapman 2006-07-05 20:20:20 UTC

FYI, a little more info...

If you do not have the sysrq key enabled a "break" does not cause the hang. 
But, if sysrq key is enabled (i.e. by adding kernel.sysrq = 1 to
/etc/sysctl.conf) we get then hang when we send a "break".

Comment 4 Doug Chapman 2006-08-31 19:19:21 UTC

This appears to be working now.  Verified in 2.6.17-1.2600.fc6.