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Cisco Bug: CSCvs81791 - Fix for kernel driver issue causing wake up for empty block, packet too large to process

Last Modified

Sep 11, 2020

Products (1)

  • Cisco Cloud Services Router 1000V Series

Known Affected Releases


Description (partial)

In extremely rare cases, a packet that is too large to handle is passed to the router. This is unexpected behavior so the router was never prepared to handle this case. This will cause traffic to stop passing and lock up.

arp will stop working

show int gi3 controller

 DPIF Rx Drop 21650 Packets 359735968    <<<<< drop counter increment when ping

show platform hardware qfp active datapath infrastructure sw-nic

instant rx drop 773 pkt 773   <<<<<< rx drop counter increment

from syslog messages:

Jun  9 14:05:41.080 GMT: %IOSXE-3-PLATFORM: R0/0: kernel: tpacket_rcv: packet too big, clamped from 15366 to 12158. macoff=82

This has only been seen with Azure service but it is possible to happen in any platform.
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