linux/drivers/s390
Heiko Carstens 94c163663f s390/memory hotplug: prevent offline of active memory increments
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>
Cc: stable@vger.kernel.org # 2.6.39+
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-04-26 09:07:10 +02:00
..
block s390/dasd: fix hanging device after resume with internal error 13 2013-04-17 14:07:34 +02:00
char s390/memory hotplug: prevent offline of active memory increments 2013-04-26 09:07:10 +02:00
cio s390/css: move subchannel lock allocation 2013-04-17 14:07:34 +02:00
crypto s390/irq: remove split irq fields from /proc/stat 2013-01-08 10:57:07 +01:00
kvm All trivial, thanks to the stuff which didn't quite make it time. 2013-02-26 14:49:12 -08:00
net qeth: fix qeth_wait_for_threads() deadlock for OSN devices 2013-04-08 17:16:57 -04:00
scsi s390/time: rename tod clock access functions 2013-02-14 15:55:10 +01:00
Makefile