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Cisco Bug: CSCvt66740 - fib_mgr, ipv4_ma process blocked while removing tunnel-te interfaces

Last Modified

Sep 07, 2020

Products (1)

  • Cisco ASR 9000 Series Aggregation Services Routers

Known Affected Releases


Description (partial)


Multiple processes blocked on fib_mgr process. fib_mgr IPv4 thread is constantly busy and so nothing else is getting processed.

1)	Topology:
<- Te tunnels ->
<- Gre tunnels ->

2)	Repro steps:
GRE interfaces(100) with different loopback interfaces and have tunnel-te (1000) using same loopback and with auto announce.
To avoid tunnel over tunnel, trying to remove the tunnel-te config ? the fib_mgr would be blocked at this point. 

The reason for this busy thread is that one of the retries that originates as part of EOD from AIB or RIB can cause Pathlist to go in retry due to platform delayed backwalk. If this is where the retry originates, then doesn't follow the standard retry process of moving to slow queue. As a result, that particular queue just stays in endless retry.

There is a shut of IP or TE tunnels on the router.
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