From: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

2.6.17-rc1-mm1 hangs during boot on HP rx8620 and dl585 -- both 4 node NUMA
platforms.  Problem is in build_sched_domains() setting up the
sched_group_nodes[] lists, resulting from patch:
sched_domain-handle-kmalloc-failure.patch

The referenced patch does not propagate the "next" pointer from the head of
the list, resulting in a loop between the last 2 groups in the list.  This
causes a tight loop/hang in init_numa_sched_groups_power() because
'sg->next' never == 'group_head' when you have > 2 nodes.

This patch seems to fix the problem.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Srivatsa Vaddagir <vatsa@in.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 kernel/sched.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN kernel/sched.c~sched_domain-handle-kmalloc-failure-fix kernel/sched.c
--- a/kernel/sched.c~sched_domain-handle-kmalloc-failure-fix
+++ a/kernel/sched.c
@@ -6089,7 +6089,7 @@ static int build_sched_domains(const cpu
 			}
 			sg->cpu_power = 0;
 			sg->cpumask = tmp;
-			sg->next = prev;
+			sg->next = prev->next;
 			cpus_or(covered, covered, tmp);
 			prev->next = sg;
 			prev = sg;
_