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Commit 54eed6cb authored by Petr Holasek's avatar Petr Holasek Committed by Ingo Molnar
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x86/numa: Add constraints check for nid parameters 



This patch adds constraint checks to the numa_set_distance()
function.

When the check triggers (this should not happen normally) it
emits a warning and avoids a store to a negative index in
numa_distance[] array - i.e. avoids memory corruption.

Negative ids can be passed when the pxm-to-nids mapping is not
properly filled while parsing the SRAT.

Signed-off-by: default avatarPetr Holasek <pholasek@redhat.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Anton Arapov <anton@redhat.com>
Link: http://lkml.kernel.org/r/20111208121640.GA2229@dhcp-27-244.brq.redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 54c29c63

arch/x86/mm/numa.c

+6 −4
Original line number Diff line number Diff line
@@ -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;

	}