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IV48360: FIN-URG-ACK STORM CAUSES SYSTEM HANG APPLIES TO AIX 6100-08

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APAR status

  • Closed as program error.

Error description

  • System could hang with a stack similar to,

--- CPU #8 ---
pvthread+794800 STACK:
[00575764]slock+000104 (0000000000000003,
F1000815B0232FF0 [??])
[000090C4].disable_lock+0000C0 ()
[05E13DA8]in_pcbhashlookup3+0003E8 (??, ??, ??, ??, ??,
??, ??, ??)
[05E8D6D4]tcp_input0+000AD4 (??, ??, ??, ??)
[05E965E4]tcp_input+000064 (F1000E008FAD3000,
0000001400000014)
[05DEC04C]ipintr_noqueue_post_fw+0009CC
(000000000529E490,
F1000E008FAD3000, F1000815B02339C0)
[05DED300]ipintr_noqueue+000120 (??, ??, ??)
[05DED4F0]ipintr+0000F0 ()
[0019CA0C]i_offlevel+00012C (??, ??)
[0019C54C]i_softmod+0005CC ()
[001EDACC]flih_util+000258 ()

Local fix

  • 



Problem summary


    

  • System could hang with a stack similar to,
--- CPU #8 ---
pvthread+794800 STACK:
 00575764 slock+000104 (0000000000000003,
F1000815B0232FF0  ?? )
 000090C4 .disable_lock+0000C0 ()
 05E13DA8 in_pcbhashlookup3+0003E8 (??, ??, ??, ??, ??,
??, ??, ??)
 05E8D6D4 tcp_input0+000AD4 (??, ??, ??, ??)
 05E965E4 tcp_input+000064 (F1000E008FAD3000,
0000001400000014)
 05DEC04C ipintr_noqueue_post_fw+0009CC
(000000000529E490,
F1000E008FAD3000, F1000815B02339C0)
 05DED300 ipintr_noqueue+000120 (??, ??, ??)
 05DED4F0 ipintr+0000F0 ()
 0019CA0C i_offlevel+00012C (??, ??)
 0019C54C i_softmod+0005CC ()
 001EDACC flih_util+000258 ()
Also there will be FIN-URG-ACK network storm

    



Problem conclusion


    

  • While retransmitting FIN, Code is modified  to check whether we
have already received ACK for the previous FIN and it was not
processed correctly. In this case restore the tcp connection's
state and retransmit FIN. This avoids FIN-URG-ACK storm.

    



Temporary fix


    

  • 



Comments


    

  • 6100-08 - use AIX APAR IV48360
7100-01 - use AIX APAR IV35942
7100-02 - use AIX APAR IV49185

    



APAR Information




    

  • APAR number
    IV48360
    • 

  • Reported component name
    AIX 610 STD EDI
    • 

  • Reported component ID
    5765G6200
    • 

  • Reported release
    610
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Submitted date
    2013-09-12
    • 

  • Closed date
    2013-09-12
    • 

  • Last modified date
    2014-02-17
    • 





    

  • APAR is sysrouted FROM one or more of the following:
    

    
IV35942
    

    • 

  • APAR is sysrouted TO one or more of the following:
    

    • 



Fix information


    

  • Fixed component name
    AIX 610 STD EDI
    • 

  • Fixed component ID
    5765G6200
    • 



Applicable component levels


    

  • R610  PSY  U859520
       UP14/02/17  I  1000
    • 



PTF to Fileset Mapping








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            17 February 2014
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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