Move the memset checks over to work against the statement.  Also add
checks for 0 and 1 used as lengths.  Generally these indicate badly
ordered parameters.
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>