IV22691: DSI IN __MEMCPY64 VIA M_CAT AND IP_REASS APPLIES TO AIX 7100-01

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Panic is in memmove64 when called from m_cat being called
  from ip_reass.
  
  One such stack is:
  
  pvthread+011700 STACK:
  [0000F4D4]___memmove64+0000D4 ()
  [004F42C4]m_cat+0000E4 (??, ??)
  [0458AF30]ip_reass+000A30 (??)
  [0458BD98]ipintr_noqueue_post_fw+0006B8
  (F1000A058AA00B18,
   F10005005C634E00,
     F1000A001AB47F40)
  [0458D2A0]ipintr_noqueue+000120 (??, ??, ??)
  [0458E8BC]in_newstack+000020 ()
  [04587390]in_flip_and_run+000070 (??, ??, ??)
  [04586728]dogisr+0003C8 (F1000A001993C068,
  F10005005C634E00,
     F100050008702000)
  [04412BD8]eth_std_receive+000378 (??, ??, ??)
  [04410BA8]eth_receive+0001A8 (??, ??)
  [043EB230]rx_handler+000790 (??, ??)
  [043ED8D4]goent_slih+000794 (??)
  [0026752C]i_poll_soft+00012C (??)
  [00266E40]i_softmod+000620 ()
  [00141C8C]flih_util+000258 ()
  
  Many factors need to be involved at the same time.
  The errctrl for netmalloc.police needs to be detail or
  higher.  There must be some fragments being promoted.  In
  this case, the 2K memory fragment was being promoted to
  a full page.  The network must also be fragmenting the
  packets for some reason which implies that PMTU is turned
  off or is somehow not being 100% effective.
  

Local fix

• A number of possible local work around.  Turn down the
  errctrl for netmalloc.police component, turn off page
  promotion of 2K pages, make sure IP fragmentation does
  not occur.
  

Problem summary

• System crash with following stack
  
  pvthread+011700 STACK:
   0000F4D4 ___memmove64+0000D4 ()
   004F42C4 m_cat+0000E4 (??, ??)
   0458AF30 ip_reass+000A30 (??)
   0458BD98 ipintr_noqueue_post_fw+0006B8
  (F1000A058AA00B18,
   F10005005C634E00,
     F1000A001AB47F40)
   0458D2A0 ipintr_noqueue+000120 (??, ??, ??)
   0458E8BC in_newstack+000020 ()
   04587390 in_flip_and_run+000070 (??, ??, ??)
   04586728 dogisr+0003C8 (F1000A001993C068,
  F10005005C634E00,
     F100050008702000)
   04412BD8 eth_std_receive+000378 (??, ??, ??)
   04410BA8 eth_receive+0001A8 (??, ??)
   043EB230 rx_handler+000790 (??, ??)
   043ED8D4 goent_slih+000794 (??)
   0026752C i_poll_soft+00012C (??)
   00266E40 i_softmod+000620 ()
   00141C8C flih_util+000258 ()
  

Problem conclusion

• Network memory alloc code is mofied to return the exact size
  of the memory that is allocated. This prevents IP layer from
  accessing the unallocated memory and also prevents the system
  from crash
  

Temporary fix

Comments

APAR Information

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

  IV15809

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

Fix information

• Fixed component name

  AIX V7.1

• Fixed component ID

  5765H4000

Applicable component levels

• R710 PSY U847987

     UP12/07/17 I 1000

PTF to Fileset Mapping

• U847987 bos.mp64 7.1.1.16