A fix is available
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
IV53403
Reported component name
AIX V7.1
Reported component ID
5765H4000
Reported release
710
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2013-12-16
Closed date
2013-12-16
Last modified date
2014-05-23
APAR is sysrouted FROM one or more of the following:
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 U858978
UP14/05/22 I 1000
PTF to Fileset Mapping
U858978 bos.mp64 7.1.3.15
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Document Information
Modified date:
23 May 2014