tree c17cbd22bc897bdf6644e242bbd086e4197ba3f5
parent 15610c86fa83ff778eb80d3cfaa71d6acceb628a
author Toshi Kani <toshi.kani@hp.com> 1378934509 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1378940259 -0700

mm/hotplug: verify hotplug memory range

add_memory() and remove_memory() can only handle a memory range aligned
with section.  There are problems when an unaligned range is added and
then deleted as follows:

 - add_memory() with an unaligned range succeeds, but __add_pages()
   called from add_memory() adds a whole section of pages even though
   a given memory range is less than the section size.
 - remove_memory() to the added unaligned range hits BUG_ON() in
   __remove_pages().

This patch changes add_memory() and remove_memory() to check if a given
memory range is aligned with section at the beginning.  As the result,
add_memory() fails with -EINVAL when a given range is unaligned, and does
not add such memory range.  This prevents remove_memory() to be called
with an unaligned range as well.  Note that remove_memory() has to use
BUG_ON() since this function cannot fail.

[akpm@linux-foundation.org: avoid printk warnings]
Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>