Bug 49061 – serial port with -clocal hangs machine

Bug 49061 - serial port with -clocal hangs machine

Summary:	serial port with -clocal hangs machine

Status:	CLOSED WORKSFORME

Aliases:	None

Product:	Red Hat Linux
Classification:	Retired
Component:	kernel (Show other bugs)
Sub Component:
Version:	7.1
Hardware:	i386 Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Arjan van de Ven
QA Contact:	Brock Organ
Docs Contact:

URL:
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Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2001-07-13 07:42 EDT by paulh
Modified:	2007-04-18 12:34 EDT (History)
CC List:	1 user (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2003-06-06 10:40:18 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
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Description paulh 2001-07-13 07:42:03 EDT

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 08:15:35 EST

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 10:40:18 EDT

No reply in over a year, closing

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