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IV88047: AT JOB SCHEDULED FAR IN THE FUTURE CAUSES CRON HANG / CPU USE APPLIES TO AIX 7200-00

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APAR status

  • Closed as program error.

Error description

  • cron will hang in the el_add function if a job far in
the future is scheduled:


# echo "echo test" | at now + 125 years
Job root.5396951176.a will be run at Sun Jan  8
  11:06:16 CST 2141.

# procstack 9437280
9437280: /usr/sbin/cron
0x000000010000e904  el_add(0x1100316b0, 0x141aef088,
0x900000009) + 0xc4
0x0000000100003134  add_atevent(0x1100339b0,
0x11000698a, 0x141aef088) + 0x274
0x0000000100006ec4  mod_atjob(0x11000698a) + 0x544
0x000000010000746c  msg_wait() + 0x34c
0x0000000100008258  idle(0x3c, 0x568fec78) + 0x38
0x0000000100009e74  main(0x100000001, 0xffffffffffffc58)
 + 0x7d4
0x00000001000002b0  __start() + 0x70

It will loop endlessly in that spot, consuming CPU.

Local fix

  • Remove the problematic at job with 'at -r <jobname>', and
then kill cron to restart it.

Problem summary

  • cron daemon consumes lot of CPU if we schedule a job far in the
future.

Problem conclusion

  • Modified the code to fix this problem.

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV88047
    • 

  • Reported component name
    AIX V7.2
    • 

  • Reported component ID
    5765CD200
    • 

  • Reported release
    720
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Submitted date
    2016-08-15
    • 

  • Closed date
    2016-08-15
    • 

  • Last modified date
    2017-01-20
    • 





    

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

    
IV81534
    

    • 

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

    • 



Fix information


    

  • Fixed component name
    AIX V7.2
    • 

  • Fixed component ID
    5765CD200
    • 



Applicable component levels


    

  • R720  PSY  U872573
       UP17/01/18  I  1000
    • 



PTF to Fileset Mapping








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            10 September 2025
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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