Avi Service Engine crash at ngx_http_set_keepalive due to buffer chain loop

Products

• VMware Avi Load Balancer

Issue/Introduction

• Avi Service Engine (SE) failed event is generated. 
• On Avi Controller UI under Administration > Support > Crash Reports, a stacktrace similar to below is noticed: 
  
  

  Core was generated by `se dp: worker process 1:
  Program terminated with signal SIGABRT, Aborted.
  #0 0x000055a4bda2d503 in ngx_http_set_keepalive (r =< optimized out>) at service_engine/nginx/src/http/ngx_http_request.c:4009
  
  [Current thread is 1 (Thread 0x7f31a8cdef40 (LWP 3282) ) ]
  
  #0 0x000055a4bda2d503 in ngx_http_set_keepalive (r =< optimized out>) at service_engine/nginx/src/http/ngx_http_request.c:4009
  
  #1 ngx_http_finalize_connection (r =< optimized out>) 
  
  #2 0x000055a4bdab9352 in ngx_http_upstream_handler 
  
  #3 0x000055a4bda0efd6 in ngx_ipstk_dispatch_event 

• We may also notice a se_agent crash followed by above se_dp crash. 

Environment

Avi Load Balancer Version >= 31.1.1

Cause

• The crash is caused when large pipeline requests are processed.
• It is triggered due to a buffer chain loop. 

Resolution

• The bug is fixed in 32.1.1 and is release noted under AV-255883 : 
   Release-notes-for-avi-load-balancer-version-32-1-1