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Description of problem: with CONFIG_NUMA=n and memcg and transparent hugepage enabled, there could be a double free later leading to VM_BUG_ON in get_page().

How reproducible: only reproducible on x86-64 with CONFIG_NUMA=n but all x86-64 kernels with transparent hugepage support enabled should have CONFIG_NUMA=y. So it shouldn't be reproducible.


Steps to Reproduce:
1. build RHEL6 with CONFIG_NUMA=n, CONFIG_TRANSPARENT_HUGEPAGE=y
2. enable memcg
3. exaust the memcg limit from regular allocations and swapout
4. swapin
5. after swapin khugepaged will fail the compaction with memcg exausted -> bug
  
Actual results:

double free and oops

Expected results:

khugepaged should fail silently without double free or oopses


Additional info: It shouldn't be reproducible in RHEL6/6.1 because all x86-64 kernels have CONFIG_NUMA=y.

Fix posted to rhkernel-list with Message-ID: <20110315175252.GQ10696>.

This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.

Patch(es) available on kernel-2.6.32-128.el6

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0542.html