lkml.org 
[lkml]   [2010]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 12/12] driver core: numa: fix BUILD_BUG_ON for node_read_distance
Date
From: David Rientjes <rientjes@google.com>

node_read_distance() has a BUILD_BUG_ON() to prevent buffer overruns when
the number of nodes printed will exceed the buffer length.

Each node only needs four chars: three for distance (maximum distance is
255) and one for a seperating space or a trailing newline.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/node.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/base/node.c b/drivers/base/node.c
index ad43185..93b3ac6 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -165,8 +165,11 @@ static ssize_t node_read_distance(struct sys_device * dev,
int len = 0;
int i;

- /* buf currently PAGE_SIZE, need ~4 chars per node */
- BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);
+ /*
+ * buf is currently PAGE_SIZE in length and each node needs 4 chars
+ * at the most (distance + space or newline).
+ */
+ BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);

for_each_online_node(i)
len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
--
1.7.0.2


\
 
 \ /
  Last update: 2010-03-19 16:23    [from the cache]
©2003-2011 Jasper Spaans