Cisco Bug: CSCsz30515 - SUP720 crash due to tsptun_frr_process process hang
Jan 24, 2017
- Cisco IOS
Known Affected Releases
Symptom: customer running 12.2(18)SXF14 and later special image including 12.2(18)SXF16 has observed SUP720 crashes with following messages %CPU_MONITOR-SP-6-NOT_HEARD: CPU_MONITOR messages have not been heard for 31 seconds [6/1] Apr 24 15:54:20.295 UTC: %CPU_MONITOR-SP-6-NOT_HEARD: CPU_MONITOR messages have not been heard for 61 seconds [6/1] Apr 24 15:54:48.627 UTC: %CPU_MONITOR-SP-6-NOT_HEARD: CPU_MONITOR messages have not been heard for 90 seconds [6/1] Apr 24 15:55:14.955 UTC: SP: icc_send_request_internal: ipc_send_rpc_blocked failed, result 6 Apr 24 15:55:14.959 UTC: SP: -Traceback= 404F5BF0 404F5DA8 404F6028 403AC090 403AC7DC The failure to respond to CPU_MONITOR messages occurs because the RP does not respond to heartbeats because it is stuck here: %SYS-2-INTSCHED: 'idle' at level 2 -Process= "LSP Tunnel FRR", ipl= 2, pid= 161 -Traceback= 41D7FCA0 41069610 42141640 %SYS-2-INTSCHED: 'idle' at level 2 -Process= "LSP Tunnel FRR", ipl= 2, pid= 161 -Traceback= 41D7FCA0 41069610 42141640 Conditions: The crashes occur during configuration activities on heavily loaded routers but there is no clear triggering condition, neither a sequence of commands nor a network event. Neither we nor the customer can reproduce the issue in a lab situation. The "LSP_Tunnel FRR" process handles LSPs (Label Switched Paths) configured for FRR (Fast ReRoute) using MPLS Traffic-Engineering. The affected router and the other routers in this network are not configured to run MPLS Traffic-Engineering, nor Fast ReRoute. This fix (CSCsz30515) prevents the "LSP Tunnel FRR" process from running unless an interface protected by FRR experiences a "DOWN" event and constitutes an optimization of the Cisco IOS software. The underlying cause of this problem ("LSP Tunnel FRR" process stuck, resulting in reload) was determined to be CSCek68108.
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