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Cisco Bug: CSCul70782 - Bulkstats CLI hanging and eventually bulkstats arent getting generated

Last Modified

Dec 25, 2016

Products (1)

  • Cisco ASR 5000 Series

Known Affected Releases

15.0(100) 15.0(14)

Description (partial)

Symptom:
Customer upgraded node to R15.0.52124. After this node observed sessmgr and bulkstats crashes. From DE analysis, it was observed that there is some do-while loop issue in dcca code.
mgmt_acsctrl_get_acs_dcca_group_stats
{
  do {
    sn_msg_call_blocking_vector(..., acs_dcca_stats_cb, &state, ...);
  } while(state.header.end_of_list != TRUE);
}
Analysis from DE Team:
"Note that if the do-while loop doesn't break, then the bulk-stat task, which is exercising this loop will eternally be stuck in making blocking-vector calls to all sessmgrs. This will not result in the other usual SIGABRT(), which happens on a tight loop, as the sn_msg_call..() will effect heart-beating, but this bulkstat task will otherwise not pick up any messages from outside world due to the nature of blocking-call, and hence will result in ager-whining like we see here. 

Just doubly check all logic that handles how state.header.end_of_list is set to TRUE in both the handler function at sessmgr and most importantly on how the call-back function - acs_dcca_stats_cb() consolidates multiple responses from different sessmgrs into a single state. Pickup all corner cases you can imagine like one sessmgr going out-of-sync with rest etc.. and ensure this call is resilient to all imaginable conditions.
"

Conditions:
--Upgrade from R14.0.51375 to R15.0.52124 of MME/SGSN combo node. 
--Bulkstats were pushed from WEM15.0 into ASR5k node.
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