IV53400: SIZEHED IN NET_KMEM_UNHIDE IF SIZE IS NOT ALIGNED WITH HEAP APPLIES TO AIX 6100-09

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When doing large memory side allocation, and MODS is turned on,
  at the time when memory is freed, machine can crash in
  net_kmem_unhide() in malloc_thread.
  
  Crash only happens with a combination of these conditions to be
  true:  a) MODS is turned on at running time. on running box,
  before the test:  errctrl -c netmalloc errchecklevel=7 On the
  running box, there are 2 page size heaps to work with (4K and
  64K) b) large allocation of size > 128K bytes. For example
  2252K c) memory pinned is from 64K page size heap.  d) memory
  address returned in net_malloc() is 64K page size aligned
    (e.g. F1000E0031220000).  e) And the request memory size is
  not a multiple of 64K page
    (e.g. 2252K/64=35.187 is not 64KB aligned)
  

Local fix

Problem summary

• When doing large memory side allocation, and MODS is turned on,
  at the time when memory is freed, machine can crash in
  net_kmem_unhide() in malloc_thread.
  
  Crash only happens with a combination of these conditions to be
  true:  a) MODS is turned on at running time. on running box,
  before the test:  errctrl -c netmalloc errchecklevel=7 On the
  running box, there are 2 page size heaps to work with (4K and
  64K) b) large allocation of size > 128K bytes. For example
  2252K c) memory pinned is from 64K page size heap.  d) memory
  address returned in net_malloc() is 64K page size aligned
    (e.g. F1000E0031220000).  e) And the request memory size is
  not a multiple of 64K page
    (e.g. 2252K/64=35.187 is not 64KB aligned)
  

Problem conclusion

• Before hiding the memory, need to validation if memory is from
  64K page size heap, the size to be hid should be aligned
  with 64KB boundary.
  

Temporary fix

Comments

• 6100-09 - use AIX APAR IV53400
  6100-09 - use AIX APAR IV53400
  6100-09 - use AIX APAR IV53400
  7100-03 - use AIX APAR IV53403
  

APAR Information

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

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

  IV53403

Fix information

• Fixed component name

  AIX 610 STD EDI

• Fixed component ID

  5765G6200

Applicable component levels

• R610 PSY U859304

     UP14/05/21 I 1000

PTF to Fileset Mapping

• U859304 bos.mp64 6.1.9.15