[PATCH v3] NUMA x86: add constraints check for nid parameters

[Petr Holasek <pholasek@redhat.com>]

This patch adds constraints checks for numa_set_distance()
function. It emits warning and avoids a store to a negative
index in numa_distance[] array. Negative ids can be passed when
pxm-to-nids mapping is not properly filled while parsing the SRAT.

Signed-off-by: Petr Holasek <pholasek@redhat.com>
---
 arch/x86/mm/numa.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index fbeaaf4..cdc0054 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -430,8 +430,9 @@ static int __init numa_alloc_distance(void)
  * calls are ignored until the distance table is reset with
  * numa_reset_distance().
  *
- * If @from or @to is higher than the highest known node at the time of
- * table creation or @distance doesn't make sense, the call is ignored.
+ * If @from or @to is higher than the highest known node or lower than zero
+ * at the time of table creation or @distance doesn't make sense, the call
+ * is ignored.
  * This is to allow simplification of specific NUMA config implementations.
  */
 void __init numa_set_distance(int from, int to, int distance)
@@ -439,8 +440,9 @@ void __init numa_set_distance(int from, int to, int distance)
 	if (!numa_distance && numa_alloc_distance() < 0)
 		return;
 
-	if (from >= numa_distance_cnt || to >= numa_distance_cnt) {
-		printk_once(KERN_DEBUG "NUMA: Debug: distance out of bound, from=%d to=%d distance=%d\n",
+	if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
+			from < 0 || to < 0) {
+		pr_warn_once("NUMA: Warning: node ids are out of bound, from=%d to=%d distance=%d\n",
 			    from, to, distance);
 		return;
 	}
-- 
1.7.6.4