IBM Support

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

A fix is available

Subscribe

You can track all active APARs for this component.

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 number

    IV53400

  • Reported component name

    AIX 610 STD EDI

  • Reported component ID

    5765G6200

  • Reported release

    610

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2013-12-16

  • Closed date

    2013-12-16

  • Last modified date

    2014-05-22

  • 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



Document information

More support for: AIX Enterprise Edition

Software version: 610

Operating system(s): AIX

Reference #: IV53400

Modified date: 22 May 2014