[Devel] [PATCH 03/39] sched/numa: Fix initialization of sched_domain_topology for NUMA

[Andrey Ryabinin]

From: Vincent Guittot <vincent.guittot at linaro.org>

commit c515db8cd311ef77b2dc7cbd6b695022655bb0f3 upstream.

Jet Chen has reported a kernel panics when booting qemu-system-x86_64 with
kvm64 cpu. A panic occured while building the sched_domain.

In sched_init_numa, we create a new topology table in which both default
levels and numa levels are copied. The last row of the table must have a null
pointer in the mask field.

The current implementation doesn't add this last row in the computation of the
table size. So we add 1 row in the allocation size that will be used as the
last row of the table. The kzalloc will ensure that the mask field is NULL.

Reported-by: Jet Chen <jet.chen at intel.com>
Tested-by: Jet Chen <jet.chen at intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot at linaro.org>
Signed-off-by: Peter Zijlstra <peterz at infradead.org>
Cc: fengguang.wu at intel.com
Link: http://lkml.kernel.org/r/1399972261-25693-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Andrey Ryabinin <aryabinin at odin.com>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index bbb6fc3..0358edd 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6829,7 +6829,7 @@ static void sched_init_numa(void)
 	/* Compute default topology size */
 	for (i = 0; sched_domain_topology[i].mask; i++);
 
-	tl = kzalloc((i + level) *
+	tl = kzalloc((i + level + 1) *
 			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
 	if (!tl)
 		return;
-- 
2.4.6