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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-04-25 10:03:15 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-05-07 20:33:06 -0700
commit5e5d3ee63ece3bcc2141dcd08306ecdf7ec30dcc (patch)
tree38fd15243a6dcaff119a4456443b2fd2f57771fe /arch
parent498f9e0f5de07158e260a3066b46e069fc48f182 (diff)
downloadvexpress-lsk-5e5d3ee63ece3bcc2141dcd08306ecdf7ec30dcc.tar.gz
s390/memory hotplug: prevent offline of active memory increments
commit 94c163663fc1dcfc067a5fb3cc1446b9469975ce upstream. In case a machine supports memory hotplug all active memory increments present at IPL time have been initialized with a "usecount" of 1. This is wrong if the memory increment size is larger than the memory section size of the memory hotplug code. If that is the case the usecount must be initialized with the number of memory sections that fit into one memory increment. Otherwise it is possible to put a memory increment into standby state even if there are still active sections. Afterwards addressing exceptions might happen which cause the kernel to panic. However even worse, if a memory increment was put into standby state and afterwards into active state again, it's contents would have been zeroed, leading to memory corruption. This was only an issue for machines that support standby memory and have at least 256GB memory. This is broken since commit fdb1bb15 "[S390] sclp/memory hotplug: fix initial usecount of increments". Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
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