Bug 49061

Summary:	serial port with -clocal hangs machine
Product:	[Retired] Red Hat Linux	Reporter:	paulh
Component:	kernel	Assignee:	Arjan van de Ven <arjanv>
Status:	CLOSED WORKSFORME	QA Contact:	Brock Organ <borgan>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.1	CC:	rmk
Target Milestone:	---
Target Release:	---
Hardware:	i386
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2003-06-06 14:40:18 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 paulh 2001-07-13 11:42:03 UTC

From Bugzilla Helper:
User-Agent: Mozilla/4.76 [en] (X11; U; Linux 2.4.2-ieee1394 i686)

Description of problem:
Setting clocal off on a serial port makes the port inaccessible and
eventually panics
the kernel

How reproducible:
Always

Steps to Reproduce:
1.stty -a </dev/ttyS0
2.stty -clocal </dev/ttyS0
3.stty -a </dev/ttyS0
	

Actual Results:  The second stty -a produced no output. User software which
repeatedly tried to
open() this port eventually caused kernel panic


Expected Results:  Second stty-a gives same results as second one except
-clocal is reported

Additional info:

This bug was noticed whilst debugging Ricardo Fachetti's libmodem library.
Software
under development would crash prematurely leaving clocal off on the port.

There are 2 ways to free the port - reboot or run minicom and killall it
after it has opened the port.

Comment 1 Russell King 2001-11-29 13:15:35 UTC

unsetting clocal makes the open block until the attached device asserts the DCD
signal.

Could you supply details of the panic, and a method that causes it please?

Thanks.

Comment 2 Alan Cox 2003-06-06 14:40:18 UTC

No reply in over a year, closing