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|Affected OS Type
||Affected Release Number
3.18.1aSP, 3.18.1SP, 3.18.1S, 3.15.0S, 3.18.0SP, 3.17.0S, 3.18.0aS, 3.18.0S, 3.16.1S, 3.15.1S, 3.17.1S, 3.16.0S
cBR-8 Cisco IOS XE Release:
3.18.2aSP / 15.6(2)SP2a
has the fix as well as later releases.
||SUP Crashed due to IPv6 list freed during v6list removing|
The cBR-8 Converged Broadband Router Supervisor card might crash due to memory corruption in the DHCPv6 (Dynamic Host Configuration Protocol version 6) client or DHCPv6 process under these circumstances:
- Upon receipt of a DHCPv6 message from the cable side
- Upon DHCPv6 lease query response from the DHCPv6 server side
When the IPv6 list is removed from the cable subscriber database, related to the DHCPv6 client in DHCPv6 solicit or DHCPv6 lease query response messages, the subscriber database entry is synchronized with the standby Supervisor and the cable line card.
If the process suspend occurs in this synchronization phase, under certain conditions such as at high CPU level, the IPv6 list might get freed elsewhere as a result of situations such as cable modem offline. When the process that uses this IPv6 list resumes, the freed IPv6 list is inadvertently accessed again which causes the Supervisor card to crash.
The issue can affect active and standy Supervisor cards.
Affected releases are listed in this table.
|Impacted cBR-8 Release List
|Cisco IOS® XE 3.15.0S / 15.5(2)S
|Cisco IOS XE 3.15.1S / 15.5(2)S1
|Cisco IOS XE 3.16.0S / 15.5(3)S
|Cisco IOS XE 3.16.1S / 15.5(3)S1
|Cisco IOS XE 3.16.2S / 15.5(3)S2
|Cisco IOS XE 3.17.0S / 15.6(1)S
|Cisco IOS XE 3.17.1S / 15.6(1)S1
|Cisco IOS XE 3.18.0S / 15.6(2)S
|Cisco IOS XE 3.18.0aS / 15.6(2)S0a
|Cisco IOS XE 3.18.1S / 15.6(2)S1
|Cisco IOS XE 3.18.0SP / 15.6(2)SP
|Cisco IOS XE 3.18.1SP / 15.6(2)SP1
|Cisco IOS XE 3.18.1aSP / 15.6(2)SP1a
Note: cBR-8 Cisco IOS XE Releases 3.18.2aSP / 15.6(2)SP2a and later do not exhibit this issue.
A Supervisor card crash, with a segmentation fault at the DHCPv6 client process or DHCPv6 relay process, is reported in crashinfo with these messages:
UNIX-EXT-SIGNAL: Segmentation fault(11), Process = DHCPv6 client
UNIX-EXT-SIGNAL: Segmentation fault(11), Process = DHCPv6 Relay
Cisco recommends that customers who use IPv6 features upgrade to Cisco IOS XE 3.18.2aSP or a later release that contains the fix. See this action table.
cBR-8 Software Download Link
The show version CLI command displays the current software version that runs on the cBR-8 router, as shown in this example:
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:
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