In sched_exec, schedstat_inc will dereference a null pointer if no domain
is found with the SD_BALANCE_EXEC flag set.  This was exposed during
testing of the previous patches where cpus are temporarily attached to a
dummy domain without SD_BALANCE_EXEC set.
Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>