Guest

Cisco SCE 1000 Series Service Control Engine

Field Notice: FN - 62815 - SCE SCOS - SSH Activity Might Cause System Instability


May 10, 2007

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Products Affected

SCE 1010/2020 SCOS - 1.5.10

SCE 1010/2020 SCOS - 1.5.8

SCE 1010/2020 SCOS - 1.5.9

SCE 1010/2020 SCOS - 2.0.2

SCE 1010/2020 SCOS - 2.0.3

SCE 1010/2020 SCOS - 2.0.5

SCE 1010/2020 SCOS - 2.0.6

SCE 1010/2020 SCOS - 2.0.7

SCE 1010/2020 SCOS - 2.0.8

SCE 1010/2020 SCOS - 2.0.9

SCE 1010/2020 SCOS - 2.5.1

SCE 1010/2020 SCOS - 2.5.10

SCE 1010/2020 SCOS - 2.5.2

SCE 1010/2020 SCOS - 2.5.5

SCE 1010/2020 SCOS - 2.5.6

SCE 1010/2020 SCOS - 2.5.7

SCE 1010/2020 SCOS - 2.5.8

SCE 1010/2020 SCOS - 2.5.9

SCE 1010/2020 SCOS - 3.0.0

SCE 1010/2020 SCOS - 3.0.1

SCE 1010/2020 SCOS - 3.0.3

SCE 1010/2020 SCOS - 3.0.4

SCE 1010/2020 SCOS - 3.0.5

SCE 1010/2020 SCOS - 3.0.6

Problem Description

During SSH activity, which usually includes session logout and login operations, the system might end in an unstable state due to file system violation.

Background

The SCOS SSH library uses several tasks to manage SSH sessions. These tasks share file descriptors which serve as the output and input channels of the sessions. In some cases the different SSH tasks can faultily use these file descriptors and perform IO operation violations due to race condition. This may result in cases where these file descriptors are already owned by non SSH tasks and are being violated by SSH tasks.

Problem Symptoms

The symptom of this problem may appear in different forms. Once the problem appears, the system is in an inconsistent state which may result in unexpected behavior and may even result in a reboot. In some cases, the output stream of SSH sessions is written to other processes (like telnet) or vice versa, or management agent gets stuck due to memory access.

Workaround/Solution

Currently there is no existing workaround for this problem. A fix is scheduled for SCOS 3.0.7 and SCOS 3.1.0 releases. In cases where such behavior is identified, it is advised to close all SSH sessions and, in worst cases, to perform an administrative reload of the box and use telnet instead of SSH.

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

DDTS

Description

CSCsh49563 (registered customers only)

Management-agent ran out of memory - probably due to some SSH activity

Revision History

Revision

Date

Comment

1.0

10-MAY-2007

Initial Public Release

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

Receive Email Notification For New Field Notices

Product Alert Tool - Set up a profile to receive email updates about reliability, safety, network security, and end-of-sale issues for the Cisco products you specify.